Could make a more 3E - esque summoning spell.
Summons a creature for 3 rounds + 1/level, with thac0, damage and hit points increasing with level, usable once per day?
Thing is though, I think we'd have to decide what the player's familiar animal species is for them, not sure how we can let them do it or if it's worth it to try.
Wolves are probably a pretty safe bet.
Maybe then summoning a dog at lower levels, then a wolf, a winter wolf then a dire wolf? At high levels we could make a tougher critter called a
Pack Leader or something.
Faster movement speed would be fine too.
The 3E writeup suggested limited spells, shall we scrap that idea?