Big Damage Go Brrrt: Have a servant deal over 1,000,000 total damage in one attack
Fu-Sion-Ha!!: NP5 your first Servant
You're Not Supposed To Be Here Yet: Clear a Part 1 story mission using a servant introduced in Part 1.5 or Later.
Representation: Summon unique 5 Servants from the same country of origin.
The Power Of the Sun: Clear a mission using only Solar themed servants (Karna, Gawain, Ozymandias, etc.)
Mom and Dad: Meet Da Vinci and Roman
Worst Orientation Day Ever: Get past the death by PowerPoint.
Snowflake Shield: Activate Mash's NP for the first time.
Wyverns Are Just Bigger Swallows: Kill over 100 dragons in Orleans using Sasaki Kojiro.
Nightmare's Begining: Defeat Gil de Rais
Extellar Reunion: Defeat Altera using only Nero and Tamamo.
But You Have Heard of Me: Lose to Blackbeard during Okeanos.
Greek sauce, Weak sauce: Defeat Heracles without losing a single servant
We need a bigger house: Get every possible resident to move into the London flat.
The Mastermind: Confront Mage King Solomon.
ACDC: Defeat Nikola Tesla using Thomas Edison during the London singularity.
ACDC 2 Electric Boogaloo: Defeat Thomas Edison using Nikola Tesla during the America singularity
ACDC 3 High Voltage: Defeat Machine God Zeus using Nikola Tesla and Thomas Edison during the Olympus Lostbelt.
Steel Ball Run: Get from California to New York, while fielding only Rider class servants.
And This Gun I Found: Defeat an enemy with a critical hit from an Archer class servant.
White House Fight House: Defeat Mad King Cu Chulainn Alter
Why Do They Keep Shooting Me In The Dick: Use Euryale's Noble Phantasm at least 5 times during the fight against Gawain.
Shield Of Resolution: Learn the True Name of Mash's Noble Phantasm.
Indefatigable: Defeat Goddess Rhongomyniad using only the Knights of the Round Table and Mash.
Day Job: Complete all of Gilgamesh's labor requests and fully develop the city of Uruk
This Is A Mild Inconvenience: Rescue Gilgamesh from the Underworld
You Are Already Dead: Defeat an enemy by inflicting Instant Death upon them.
Mommy Issues: Defeat BEAST II Tiamat
We're In The End Game Now: Summon all your allies to the Temple of Time
The Monster Behind The Mask: Defeat BEAST I Goetia
Transient Snowflake Shield: Pick up what is left behind.
Guts, Determination, And One Big Freaking Shield: Defeat Goetia, King of Men once and for all!!
A Clear Blue Sky: Finish the story for Part 1 of Fate Grand Order.
The Dress is a Requirement: Sneak into the gala dinner undetected.
All According to Keikaku: Unravel the mystery of Moriarty's plot
Meuniere this is all your fault: Clear an Agartha mission with Astolfo, D'eon, Prince of Lanling, Nemo, Paris and Nobukatsu.
Big, Angry and Red All Over: Defeat Heracles Megalos
Curse You And Your Sudden But Inevitable Betrayal: Defeat Christopher Columbus.
Blades of Hell: Defeat the 7 Sword Masters of Shimousa
Ganryu-Jima: Defeat Sasaki Kojiro
Twist the Final Knot: Solve the mystery of Salem.
Turn the Silver Key: Defeat Abigail Williams.
I'm also putting in the achievements listed by other people here too. I'll try to filter out any repeats as best as I can.
Klingon Promotion: Enhance a servant with another servant
And Your Reward is Clothes: Unlock a Spiritron Dress
Big Spender: Use 20 4 or 5 star materials to enhance a servant at once
The Start of a Beautiful Friendship: Make one friend
Me’s a crowd: Have a support setup with at least three saberfaces
It’s just a bribe: Summon a 5 star servant using a summon ticket.
There is No Kill...: Achieve 1,000,000 Overkill Damage
Like Overkill: Achieve 1,000,000 Overgauge Damage
Is This Just Fantasy: Complete the Prologue to Cosmos in the Lostbelt.
Weren’t Expecting Special Forces: Clear any node with a Support Servant at least 20 levels above your strongest Servant.
Clear and Hold: Clear a node in the minimum amount of turns.
Better Red Than Dead: Clear a node with only Buster cards.
Blue Da Ba Dee: Clear a node with only Arts cards.
Not Easy Being Green: Clear a node with only Quick cards.
With Extreme Prejudice: Clear a node with only NP cards.
Fighting in the Shade: Defeat Tristan with only Leonidas surviving.
Seeing Double: Clear a node with two of the same Servant.
Deja Vu: Use a Servant’s Noble Phantasm in two consecutive turns.
The Very Best Kouhai: Level Mash Kyrielight to level 80.
That All You Got?: Take 0 damage from an enemy attack.
We Get There When We Get There: Clear a node in 25 turns or more.
Last Stand: Clear a node with one Servant remaining.
Arrivederci: Bid Da Vinci farewell.
A̸̫̿l̷͇̾l̷̲̄ ̸̪̀t̵̼̆h̷̰͝e̶̬͐ ̵̧͌W̴̱͒o̷͕̓r̴̛̗l̷̻̈́d̷̼͘'̶͖̕s̵̡̚ ̶͖̚Ȩ̶͛v̴̨͂i̸͉͒l̸͑͜: Summon a 0-star Servant.
Was it really worth it?: Finish Agartha without skipping cutscenes.
All Around Me Are Familiar Faces: Own your first Saberface
When Does the Battle Start?: Clear a challenge quest for the first time
Raise the Bloody Standard!: Run a team compromised entirely of French servants and win a battle.
Does the Sun Shine Above Thine Head?: Defeat Gawain without using command seals or revival quartz.
Deep Dive: Defeat Kiara without using KP debuffs.
Yesterday’s enemies can be tomorrow’s allies:Summon all the Lostbelt Kings to date.
Horus Blessing: Summon Ozymandias, Cleopatra and Nitocris.
I Was Born To Meet You: Reach Bond 15 with a Servant.
The Gacha Gotcha!: Buy Saint Quartz for the first time.
No Kill Like Overkill: Deal over 100,000 damage in a single round of Overkill status.
Over & Over: Achieve both Overkill and Overgauge status in a single turn.
Dark Soul: Trigger the Guts status 3 turns in a row with the ‘Necromancy’ Craft Essence.
Luck of the Irish: Defeat or have your own Cu Chulainn (Lancer) die while he has an active Evade status.
Look Up, Foolish Knight: Defeat Gawain in the Camelot Singularity with a full party without losing a single Servant.
Look At Me Now, Dad!: Land the final blow on Goddess Rhongomyniad with Mordred (Saber) or Mordred (Rider) in the Camelot Singularity.
Slow and Steady: Complete a battle in no less than 100 turns.
Pay To Win: use more than one saints quartz to revive your team
The Pirates Who Don't Do Anything: log in for 30 days without doing any quests
Idolmaster: Raise Elizabeth Bathory (Lancer), Elizabeth Bathory (Caster), Elizabeth Bathory (Saber), and Mecha Eli-chan Mk I or Mk II to level 100, skill 10/10/10 and NP5
The Strongest of Wills: complete the Final Singularity without ever spending money on saint quartz
What Did it Cost?: spend $300 or more on a single banner
You All Look Familiar: summon 5 saberfaces
It's Just a Bribe: summon an SSR servant with a summon ticket
It Follow Me Home, Can I Keep It?: Summon 10 free event servants.
Unlimited Critical Star Works: Gather 99 critical stars with Emiya, in a turn where only he acted.
This Servant Empty, Yeet: Defeat a servant that is child sized with Suzuka Gozen.
Pirate Ninja Robot Servant: Clear any battle with any pirate servant, any ninja servant and any mechanical servant in your party.
Paper Skin And Glass Bones: Stack at least 5 defensive debuffs on one enemy
No Time To Unpack All That: Skip 0 AP nodes 5 times.
Richest Duck in the World: Hit the maximum amount of QP you can store (999,999,999)
Well Deserved Break: Start an Event in the middle of a unfinished main story chapter (EoR Chapters apply)
I Thought We Were on Vacation?!: Clear the Shop during an event
Don’t Tell Anyone How I Live: Clear the Shop in an event during the first week.
Summer Camp Friendship: Obtain a Welfare Servant during a summer event.
Behold The Lord, High Executioner: Max out Charles Henri-Sanson and all skills to 10/10/10
Leeroy Jenkins: Lose every party member in a battle against dragon-type enemies
BLOOD FOR THE BLOOD GOD!: Have a Foreigner and Mordred in a party at the same time
Immaculate Conception: Have Jeanne, Martha, and George in a team, and have none of them take any damage
Feeling EXTRA: Summon EMIYA, Tamamo no Mae (Caster), Nero (Saber), Cu Chulainn (Lancer), Lu Bu, Francis Drake, Gawain, Robin Hood, Nursery Rhyme, Li Shuwen (Lancer), and Vlad III (EXTRA).
The Tokyo Seven: Summon Arthur Pendragon (Prototype), Arash, Brynhildr, Ozymandias, Paracelsus, Hassan of Serenity, and Jekyll.
BB Channel: Get BB to NP 5 and Max Ascension.
Pioneering Spirit: Get Paul Bunyan to NP 5 and Max Ascension.
Snowball’s Chance in Kur: Get Altera the San(ta) to NP 5 and Max Ascension.
Brand Recognition: Use a party of 6 Saberfaces.
Sakura Six: Use a party of 6 servants, containing only the following: B B, B B (Summer), Meltryllis, Mysterious Alter Ego Λ, Passionlip, Kingprotea, Parvati, and Kama.
Boatload of Fun: Use a party of 6 Argo-related servants.
In Name Only: Use a party of 6 Pseudo or Demi Servants.
New Moon: Defeat Avenger of Shinjuku using a Moon Cancer servant.
Reichenbach Turnabout: Defeat Sherlock Holmes using Archer of Shinjuku.
REGEND: Defeat Jeanne d’Arc (Alter) using the Savior of France.
Argon Coin: Admire the fleece.
Oni hunter extraordinaire : complete the point ladder in onigashima
Devotion's Reward: Enter a battle while one of your Servants is equipped with their Bond 10 CE.
Triple Threat: Chain three Noble Phantasms together.
Not Today: Have the same Servant be saved by Guts five times in a single battle.
Meteor Shower: Use Stella three times in a single battle. Yes, it's possible.
You're Going Down: Clear an entire wave with one card.
Pride of Lions: Field a team consisting entirely of versions of Artoria Pendragon.
The Cú Chu Trainn: Field a team consisting entirely of versions of Cú Chulainn.
Blademaster: Field a team of six Sabers.
Phalanx: Field a team of six Lancers.
Ranger: Field a team of six Archers.
Magi: Field a team of six Casters.
Dragoon: Field a team of six Riders.
Warcry: Field a team of six Berserkers.
Eclectic: Field a team of six Extra Class Servants.
Send In The Twins: Have Euryale and Stheno keep an enemy stunned for ten consecutive turns.
The Rare And Threatening Double Davis: Use the same NP twice in a single turn.
How Did We Get Here?: Have a battle end in a tie. Time-limited battles don't count, you've got to win and lose at the same time. Yes, it's possible!
It Can’t Be Helped!: Clear GudaGuda Honnouji
I went to the Bathory Concert and all I got was these stupid Ruptured Eardrums!: Clear Halloween 2017
Of Reindeer and Fried Chicken: Clear Christmas 2017
An Alternative Piece: Clear Da Vinci and the 7 Counterfeit Heroic Spirits
A Vacation to Die for: Clear Part 1 of Summer 2018
Back to the Future: Clear Part 2 of Summer 2018
MINASE DIE CHALLENGE: Clear Prisma Illya, then purge the event from your memory for the sake of your sanity.
End of an Era: Clear Gudaguda Meiji Isshin
Oda Protectorate: Clear Gudaguda Meiji Isshin after having exclusively supported the Oda Shogunate
Shinsengumi Cadet: Clear Gudaguda Meihi Isshin after having exclusively supported the Shinsengumi
Puppy/Deerlet in Shining Armor: Clear Halloween 2018
A Dream Made Reality: Clear Christmas 2018
Wacky Races: Clear Summer 2019 part 1
What a Load of Bull: Clear Summer 2019 part 2
Battle of the Weebs: Clear Halloween 2019
Hatred’s End: Clear Christmas 2019
by @hasmashdoneanythingwrong
Target Verified, Commencing Hostilities!: Defeat an enemy that has taunt applied to itself in one turn.
Red Team 4 Life: Deploy Amakusa, Semiramis, and Shakespear as a team.
Together in Life, Death, and War: Field any two servants that were a couple, either in a Fate entry specifically or their origin.
Big Iron: Complete a mission using only a team of gun users.
I've Come to Bargain: Defeat a boss that has defeated you more than three times.
Shadow Legends: Play a raid mission.
For a CUP!: Preform Palingenesis on a Servant
*indecipherable screeching*: Complete a mission with a team of only Berserkers
I'm Basically Robin Hood: Complete a mission with a team of only Archers
Beautiful Choice of Last Words: Complete a mission with a team of only Sabers
Be Sure to Keep that Sticker On: Complete a mission with a team of only Lancers
More Like Tomato, Tanuclear Warhead: Complete a mission with a team of only Casters
Next Time I'll Bring the Beer!: Complete a mission with a team of only Riders
So Archer Lied to Me: Complete a mission with a team of only Assassins
It’s Only A Flesh Wound!: Avoid death using Guts
I’m Invincible!: Apply invincible to a single servant
You’re a Loony: Damage an enemy with an active Invincible buff
Surprise!: Get spooked by a gold card.
Better Than Nothing: Max Limit Break a one-star Craft Essence.
Stage Two: Max Limit Break a two-star CE.
Oooo, Shiny: Max Limit Break a silver CE.
What Is Your Luck Stat?: Max Limit Break a gold CE.
Are You Okay?: Clear an Epic of Remnant or Lostbelt quest with a Buster team that does not include Merlin.
Starcrash: Clear an Epic of Remnant or Lostbelt quest with a Quick team that does not include Scathath-Skadi.
His Pills, His Hands, His Jeans: Clear an Epic of Remnant or Lostbelt quest with an Arts team that does not include Tamamo-no-Mae.
Rock-Paper-Jackhammer: Deal over 100,000 damage to a single target that resists the attacker (Special Attack is your friend for this one).
Go to Your Room!: Deal over 100,000 damage to Mordred with Artoria (any version of either).
I’m Already In My Room!: Deal over 100,000 damage to Artoria with Mordred (any version of either).
Luck EX: Purchase an SSR Servant with Unregistered Spirit Origins.
Thank You, Sir, May I Have Another?: Have a Servant survive two consecutive NPs from an enemy that fires it every turn (such as Mordred in Camelot).
How Many Times Do I Have to Kill You, Boy?: Keep Heracles alive for ten turns without support.
This Body is Made of Swords: Clear an Epic of Remnant or Lostbelt quest while fielding both versions of Emiya.
COOOOOOOOOL!: Clear an Epic of Remnant or Lostbelt quest while fielding Gilles de Rais (Caster).
by @hasspartacusdoneanythingwrong
Everyone Has One: Pick a favorite servant.
You Poor Bastard: Pick a favorite servant that hasn’t had a speaking role in two years.
We Don’t Play Favorites Here: Set your favorite to random for a week.
Come On, I Know There’s One More Line!: Tap the My Room servant Ten times in six seconds.
