You could go for a lot of Cat tokens or keep your build primarily to regular Cat creatures
Casting spells from the graveyard for two less is already strong, but granting Mayhem to every nonland card in your graveyard is absurd value
Chord of Calling is good in Commander, of course, but Ive only ever seen it used in base-green decks that go heavy on the tutors
For example, Stitch, Rock Star was first printed in The First Chapter, before being reprinted in Fabled
First of all, I definitely recommend using tweezers to apply the stamps
The last ability can find any card with the Doctor creature type, not just a card with "Doctor" in the name