Since we see more and more stories like that, isn't it time to create a tag for it? Seriously, just typing "villainess" already give us 15 results, all pretty recent, so surely more will come soon.
We could also create an otome tag instead: it would include all the shoujos happening in world with 19th-early 20th century european clothings, nobles and romance with female MC (So all the villainess stories are included in it) (I know that otome is different than that but if you find a better word, tell me) (It would also include fantasy and not-fantasy). The number is also so high that you can consider it to be it's own subgenre of shoujos. (Just the chapters on the home page right now contain: IRIS - Lady with a Smartphone; Doctor Elise: The Royal Lady with the Lamp; My Fair Footman. 3 of the subgenre on 42 releases)
Also another tag we could add is touhou: the number of touhou doujins translated is also huge. There are 630 touhou mangas on the site. (At least they are easy to find, so the tag is more for exclusion)
Edit: I didn't know if it was considered as a suggestion for the site, so I posted on the general forum for manga
EDIT: I repeat: THE TOUHOU TAG IS FOR EXCLUSION; THEY ARE EASY TO FIND BUT BOTHERSOME WHEN LOOKING FOR SOMETHING ELSE
We could also create an otome tag instead: it would include all the shoujos happening in world with 19th-early 20th century european clothings, nobles and romance with female MC (So all the villainess stories are included in it) (I know that otome is different than that but if you find a better word, tell me) (It would also include fantasy and not-fantasy). The number is also so high that you can consider it to be it's own subgenre of shoujos. (Just the chapters on the home page right now contain: IRIS - Lady with a Smartphone; Doctor Elise: The Royal Lady with the Lamp; My Fair Footman. 3 of the subgenre on 42 releases)
Also another tag we could add is touhou: the number of touhou doujins translated is also huge. There are 630 touhou mangas on the site. (At least they are easy to find, so the tag is more for exclusion)
Edit: I didn't know if it was considered as a suggestion for the site, so I posted on the general forum for manga
EDIT: I repeat: THE TOUHOU TAG IS FOR EXCLUSION; THEY ARE EASY TO FIND BUT BOTHERSOME WHEN LOOKING FOR SOMETHING ELSE