Putting this here now even though I'm kind of brain dead, so I'm sorry if I don't make much sense. I have two potentials:

Lux is a super brainiac bookish type (also Psychic/Fairy), so I think they would be adorable nerd friends together.

Nozomi is a Ninetales Vale resident, and is basically everybody's mom. Seriously. Maka is thoroughly adorable, so she'll likely adopt her in some capacity. She's also good friends with Rei, so that's another connection.