well technically, those manga aren't included in the shounen ai category (they can't be called that cuz there's really no real pairing going on)
the gen mangas that have nice BL undertones that i like are
http://www.mangago.zone/read-manga/hard_romantica/
http://www.mangago.zone/read-manga/kyou_kara_maoh/
most of mangas like those have really excellent art and story so i recommend reading them ^_^ look over my collection http://www.mangago.zone/people/tag/49344/BL+undertones/?page=1
Thank you!
If you are strictly looking for Bromance then you'll find some here -
http://www.mangago.zone/home/mangalist/26616/
I noted down which ones have Bromance in them in my reviews. BUT, If you are just looking for shounen ai then try those from here -
http://www.mangago.zone/home/mangalist/26616/
Sorry, I mentioned them both separately because I don't quite get your request. If it's shounen ai it won't be called bromance, as it has already been declared BL through it's genre. But, if it's from a non-BL category but has lots of subtle BL hints then we call it Bromance. At least, that's what I know. So, forgive me if I am wrong.
Can you recommend any shounen ai where there's a lot of bromance?