The first 2 are my favorites of all times and the others are in no particular order. If you're into yaoi, I think you've probably already read all of them since they aren't hidden gems or anything, they're all pretty popular:
- totally captivated (and the Totally Captivated dj The Last Episode)
- Ai no kusabi: I don't like tragedies but I loved this and it could be my favorite yaoi of all times (I watched the 1992 OVAs and read the novel)
- Junjou Romantica
- Sekaiichi Hatsukoi
- Katekyo!
- From Points of Three
- Honto Yajuu
- BJ alex
- Tale of the Yellow Dragon
- Back to School
- Lack of Love
I'm pretty sure I love other yaois and I remember their plots but it would take for someone to mention the title and then I'll remember everything about them which id different from yaois like this one (the reason for my original comment) which I'll remember nothing about in a couple of months. I already forgot what it's about
I agree with all the other mangas on your list but when I saw a boring manga like Back To School as one of your favourites I immediately started reading the manga above (Rain Again) which you described as something not worth it and I don’t regret it. It’s the best. How can anyone even like Back To School and not Rain Again? Don’t understand it. Well tastes differ of course Lol

Meh the story isn't bad but it's not very good either. It's just one of those yaois that you read once and forget about it.
There are yaois I remember after 9 years of reading them and this won't be one of those