Danny & Loki
The infinite realms cover not just places and dimensions but also times. The Yggdrasil (tree) has branches that are said to allow those who can walk them without getting lost the ability to travel between realms. I'm pretty sure those two would intersect somewhere.
Which means - Danny could end up finding Loki as a young man/child and being his friend and/or adopting him as a son, cousin, whatever. Or maybe he even adopts him as a father figure/mentor.
I mean - you have someone (with black hair and green eyes) who is not accepted for who they are, are constantly compared to an older sibling and told they aren't enough, belittled for the skills they do have and have worked hard for (and has a connection to magic and ice). I'm pretty sure that Danny would empathize with that. And want him to not be alone.
Maybe Danny finds him by accident. Maybe Loki is exploring on the branches of the Yggdrasil and falls into the GZ. Maybe danny was practicing opening portals and landed in Asgard in the past (and keeps going at different times and is basically Loki's secret childhood friend even though Loki is very much older than him)
OR!!
Maybe its reversed!!!
Loki is the one to find Danny. He sees a child who has to hide who they are and what they can do from parents that are openly against what he is, and what he hides being. A child with no one to teach him as he struggles to learn the powers he has (maybe a type of magic. Death magic maybe?) And then he sees the ice and knows he can help. So he does. And Loki basically adopts Danny.
