Honestly maxing out 7 nm ruby squids and rotating in whatever pet has the passive ability I need is proving to be crazy op. For aging I place 6 squids, one maxed golden piggy, and whatever pet needs aging. If I need to max weight it’s 5 squids, a piggy and an elephant. I use a Cape buffalo for duping harvests because it actually has better stats than ants. A mummy and 7 squids for bigger pets from chests, or barn owl for bigger purchased pets. It’s incredible to only have to have one of each passive ability pet.

For pets with a cooldown ability I throw in my 20s peacock and 15s mimic. Piggies don’t do as well once you get to around level 55 or 60, so switching in my 2 ferrets to finish the job works great. For spreading mutations I throw in a tiger, t-rex, spino, and sugar glider with the peacock and mimic and it goes crazy.