Well all pets give an extra in some commands like /pet /playdate and etc but if a pet was created with an extra in activity classes? For example create a butterfly that gives extra lifetime in /snooze (even if it tooks low happiness it will give you a good amount of lifetime) they could be exclusive for events pets ^^ i think it would be fun and usefull, since alot of perks end up repeting
Also a pet that gives an extra when someone gives you a stargift would be cool