This is a silly one, but: giant cats.

Give a cat with specific genes a very small chance to come out absolutely massive. They could potentially be barred from wearing clothes, to make things easier (perhaps with the option to let people submit custom clothes for them?).

They could also be barred from breeding, to make them more rare. So once in a while, you'd be scrolling through someone's cats and just see one (1) giant-massive boy, as a bit of a fun-but-mostly-useless oddity.

Did a quick sketch for a laugh image hosting broke, RIP

Convenient for players? No. Easy to implement? Probably not. A whole lot of fun? Respectfully, I would sell a kidney for this. So. Yes. IMO.

@seventeendeer omg I love this

i think if we got a species that asexually reproduced it'd be really cool.
i don't know how plausible it'd be when you factor in economy+genetic stuff -- like. would the parent's offspring be an exact clone every time? does the offspring gradually mutate with every generation similar to irl plants (this is the coolest option imo)? is the kitten just... Randomized??? would every single kitten from this species have the lonely kitten effect? would the economy react badly to a very slowly generating species?
However. i think it would be extremely funny (and slightly horrifying) if a cat did mitosis or fragmentation. what would the Start A Family prompt look like....

I wish we could auto-sort our cats in more ways besides numbers/age.
Like colors, patterns, ranks, etc

. Same. Like date they joined our collection. So I (and all of us) can know what cats we have had the longest.

Add cats with a ticked tabby pattern

May I suggest:

@Sallin woag! Cuttlecats! I love them

@Sallin Cathulhu

In terms of colour.............a wide variety of pink....I love muted rose pink colours, I would love that.