I wish there were more Re:zero fanfics with a reincarnated or reborn mc.
Favourite anime 
-Re:zero
-Overlord 
-Konosuba
-Highschool dxd 
One of my many complaints on fanfics in general is that most fanfics (especially dxd) make relationships way to fast (hell canon Issei didn't get with Rias for ages considering how obvious it was they liked each other)  and if it's a harem the author either includes too many girls and can't progress all their relationships properly or have all women immediately fall for the protagonist (typically the entire dxd cast with no build up), ideally in my opinion I think authors should progress the main characters relationships before adding any new people to a harem and my personal preference is 3 or less women and no more as if not done properly it begins to make there relationships less realistic and therefore entertaining.