Animal companions can have barding and horses in particular have access to magical horseshoes, but are there any rules stopping me from making custom magic items for other possible slots?
For example: Magic collars for wolves and dogs could act like rings and amulets. Magic caparisons for horses could act like magic cloaks.
Best Answer
The Pathfinder rules only explicitly state the slots available for humanoid creatures. However, there are two possible leads on an answer - this Paizo thread quotes an old 3.5 "Rules of the Game" article allows up to 12 slots, but the ruling in Living Greyhawk games was only slotless, animal specific, barding, and amulet (collar). I personally would go with the latter but I hate Christmas tree syndrome.