I have an entire subsection of my groups dedicated to themed pets! It started as a way to keep my regular species groups' aesthetics tidy, and has since blossomed into something all its own. Currently, said subsection includes:
Sporthorses, which is the November 2011 horse litter plus Custom Made from the previous year. Dedicated to my memories of volunteering at the World Equestrian Games in 2018, which is why most are named after FEI disciplines.

Dragonwolves, which contains the Eastern dragon-themed butterfly wolves from CNY 2011-2013 in as aesthetically pleasing an arrangement as I could manage given the date constraints.
ps artists pls make more i love these
Dance of the Hours, aka the day-night horse litter from Aug 2010. Their names are the Italian words for the time of day they represent, as a nod to the actual
Danza delle ore orchestral suite.

Close Encounters of the Third Kind, a quintet of the most bizarre aliens from Summer Vacation 2016, aka "the one where CS went to space." Sure wish I'd been here for that!

Jurassic Park, where you'll find the dino store pet set from 2016. Like "Close Encounters" before it, JP is one of my very few mixed-species groups; my strict, borderline neurotic display aesthetics simply won't allow them outside of situations like these.


That's more or less all I have so far, but they've been so fun to put together (and so good for, again, ~group aesthetics~) that I may make more in the future! Dunno if this was necessarily what you had in mind, especially if you were thinking more along the lines of Shian's skelly- and raven-themed pet groups ^^ still, I hope it helps.