I've been searching and searching for something I thought I remembered seeing before to no avail, so I'm wondering if I made it up or am confusing it with something else.

It was like a google spreadsheet that compiled a bunch of pets and their TC themes, for the purpose of other people browsing them and looking for items to add to their own similarly themed pets.

It was like this thread, but with a lot more pets and themes and I swear it was on google sheets... The Pet TC Help Masterlist! (Bring your best TCs!)

Anyone know if this exists?

Are you referring to this from the pet spotlight help thread?

OMG yes! This was it. Thank you so much, I don't know how I kept overlooking where this was at. I'm bookmarking it this time. Thanks again!