Should there be a tag/pool for characters who don't normally wear clothes wearing clothes?
As far as I can recall, it'd mostly be for MLP images, specifically for their pony versions rather than the ones from Equestria Girls. So, as Saphyr said, it'd be a rather niche pool. And I like the "Kneeless mermaids" pool. ( pool #1838 )
For the time being, I think the way to go is the current multiple tag search: "my_little_pony swimsuit", "my_little_pony socks", "mermaid shell_bikini", etc.
Pro: Marisa's bikini is super cute. Con: Ponies in swimsuits is just creepy.
Swimsuit 1What seems to be the problem?It's OK~!Since we usually don't wear anything anyway, it's fine~It's time to go home for dinner!Doesn't matter, we don't wear anything regularly after all.Ah...where did it go?Swimsuit 2I'm coming.I'm not wearing it anyway.Wait a second, don't get up before you get dressed!Higurashi No Naku Koro Ni crowdLucky Star crowdIkamusumeNon Non Biyori crowdGot it!Fluttershy's swimsuit is lost in the water.Get dressed...K-ON crowdYou're gonna catch a cold if you stay there.Do ponies wear swimsuits?Yuru Yuri crowdOn my way.What happened?To Aru Kagaku no Railgun crowd