I have a huge collection of minis. One of my sub collections is familiers. I have around 60. the Warhammer game used to have about 20 , which was the start of the collection in 1986.
So I've got all these cool little guys: what to do with them? I put a demi-plane of familiers in my game.
Even non-Wiz going there can get a familier. Surprisingly it was never a popular destination, but this is where my campaigns beasties come from.
I give them to lichs, dragons, whatever and often make them very tuff for a warm up fight for a boss fight.
Using the Pathfinder rules these days the lore of the bonded item is too great and pcs never take them
In my homebrew rules , I made them pretty powerful, but also allowed bonded item instead, again the pcs never take them. My rules even allow them to "respawn" after death like 4 times a day. Nope bonded item rules supreme(for those of you that dont know: the bonded item allows the wiz to once a day cast any spell they know spontaneously)
Some ideas on familier types (as most things on this blog, geared for low level play.
Wiz type casts spells at 1/2 L of owner
fighter tyoe 1/2 casters HP and fights as fighter caster L
messenger/ scout type Flies and is highly intelligent capable of independannt thought speech and can be any distance from caster
thief type 1/2 wiz L
cleric type can use CLW once a day
Another use I have for the minis is as "true goblyns". Goblyns more akin to western myth, fey type.