Personal References/Theory of basically which frames were either originally primes, primed during the Orokin Era, or post-Orokin primes (and unknown).
Original Primes
Sevagoth - His entire premise is he's a "ghost" of the Tempestarii and that effectively that he rotted away while trapped adrift. Protea - I don't think Granum Parvos would accept less (especially seeing as we know Protea prime existed in that thanks to TOP) then a prime and likewise had her primeness stripped by prolonged exposure to the void. Caliban - Considering he was in collaboration with the Sentients during the short era of peace they had having him initially primed makes sense. Base Caliban, also, has a bit of a decayed appearance compared to his prime too.
Orokin-Era Primes
Ash - Appears in TOP Excalibur - Appears in TOP Mag - Appears in TOP Mesa - Appears in TOP Trinity - Appears in TOP Ember - Appears in TOP Volt - Appears in TOP Khora - Appears in TOP's prelude web event. Her prime explicitly states she was made in honor of Margulis. Wisp - Appears in TOP's prelude web event. Nekros - Appears in TOP's prelude web event. Rhino - Appears in TOP's prelude web event. Ivara - Appears in TOP's prelude web event. Grendel - Lore trailer specifies he was made during the Old War was likely primed during that time. Gauss - Lore trailer specifies he was made during the Old War was likely primed during that time. Hydroid - Ballas in his prime trailer refers to their subjects so it's probably referring to the Orokin Era. Nidus - His prime described as "long-unseen" and a "primal form of infestation" of infestation which frankly could imply he's an OG Prime. But, he's atleast, Orokin era. Honestly, maybe even pre-Orokin era. Nova - Seen defending the reservoir in a quest I don't remember which one oops. I'll figure it out later. Nyx - Assuming because her brother Excalibur was primed during the Orokin era. Octavia - Probably primed during the Orokin era considering her job as the one who sounded the drums on the Night of the Naga Drums. Saryn - Likely primed in honor of Margulis like Khora. Uriel - Was primed during the Orokin era according to Roathe.
Post-Orokin Primes
Xaku - Didn't exist until after the Orokin fell and is also three seperate Warframes. Prime design has the appearance of Kintsugu. Inaros - There are statues during the Sands of Inaros quest which show base Inaros. Lavos - He litterally primed himself. Voruna - She only merged her dogs to her body during the end of the Orokin era so her prime is most likely a post-Orokin enhancement.
Weird Ones
Temple - So, Flare is not Primed. Flare is Temple. However, due to timey-wimey bullshit it's entirely possible Flare/Temple is primed during the Orokin Era.
Unknown
Atlas Banshee Baruuk Chroma Equinox Garuda Gyre - :)..................... Limbo Nokko Yareli Mirage Nezha Oberon Qorvex Revenant - Listen, even Ballas is confused by Revenant. Styanax Titania Valkyr - Technically Valkyr is a post-Orokin frame and Valkyr Prime should be Gersemi Prime but DE is a boring company so it's not that. I don't believe there is information one way or another on if she was primed in the Orokin era but I gotta relook over the quests that show primes. Vaubahn Wukong Zephyr Hildryn
