Let's be honest here, a debatable problem that we all see but don't talk about too much is originality when it comes to pets and mounts (usually). And that originality is sacrificed gear bonuses and spell cards. Just go to the commons or quest and count how many Frillasaurs, Ghultures and Bronto's are around. Though this idea mostly tackles the pet issue.
I think it would be pretty neat if there was a "Dojo" of sort where you can choose two pets. Here, you choose a "Master" pet that has a spell card or set bonus you like. Then you choose the "Pupil" who you want the ItemCard/Bonus to be spread to.
So you've chosen the two pets. (Guessing that the Master has multiple cards) The Pupil now has a chance to learn one of the ItemCards your Master possess. For example, If you choose a Boss Banshee as a Pupil, and a Dark Scaryonette as a Master, then there is a chance the Boss Banshee could learn Fuel. Doing it again, it may learn Fire beetle. Each has a chance to carry on, to a max of three cards. Doing this can't replace cards the Pupil already possess, but gives them possibly more useful cards.
And the same with gear bonuses, A Snappy Frill may be able to pass it's set bonus onto the Boss Banshee when in the dojo.
Doing the dojo would probably use a time system that scales on what the Master pet has to offer. (A Master with 3 cards and a set bonus would take longer to learn from compared to a pet that gives 1 card only.)
It's just a pet peeve of mine seeing a lot of the same pets around, when there are so many in the game to choose from. And many could match stitches as well. I personally sacrifice a bit of damage from the set bonus just so I can choose a pet that I like the look of. If this problem, and the mount one is solved, then there will be a surge of different looks again, obviously it's not as big a deal as armor, so it gets overlooked. But a pet really has the potential to make a stitch pop out! I always enjoy conversations talking about how my pets and wizards are twins.
As a final add-on, this way of pet "fusion" could lead to a time where *everyone's* pet could be special! Be the spells going with your stitch, or min-maxing one for pvp. You can go around saying I love *MY* pet, because it is truly one you took time to create.
Thanks a ton for reading through, I hope this idea can be seen and maybe even inspire more ideas from the readers. Thank you.