Since there is an increasing number of pets in the game. I would like to suggest a feature to help the active player get more pets.
When a player kills a pet gnome, the pet that is spawned should only come from the pool of available pets that the player who killed the gnome has not Mythic-ed. Then of course if a player has all available spawn-able pets at mythic the pool would default back to all.
The idea here is to reward the people that play the game without making a huge change to the way pet gnomes work, how often they appear, or where they appear