I love when the ml acts as an antagonist to the mc. I'm not talking about when the mc simply just hates him for being annoying or something, I'm talking about when he intentionally acts as an actual obstacle to the mc's goals and genuinely are the villain of the story for a while until their objectives are clear. Readers will mostly hate on them, not for being a flawed character, as you might expect people to dislike from a character who's supposed to be the mc's counterpart in a romantic relationship (for example a rapist ml) but because they're actively going against the mc's values or what was supposed to be a smooth sailing plotline. Often there might be a third party involved as well which the readers believe might be a better romantic option for the mc, alas it's inevitable.
For example:
Ilay Riegrow from Passion
Baek Cirrus from Lost In The Cloud
Fair skinned top x Darker skinned bottom recommendations pls?
https://www.mangago.me/read-manga/love_sick_dog/
https://www.mangago.me/read-manga/mr_tiger_thank_you_for_the_meal/
https://www.mangago.me/read-manga/absolutely_ruined_love/
https://www.mangago.me/read-manga/capture_me_with_an_expert_kiss/
https://www.mangago.me/read-manga/sex_with_a_virgin_otaku_can_t_be_good/
list to look through
https://www.mangago.me/home/mangalist/290509/
https://www.mangago.me/read-manga/kimi_to_iru_shima/
funny enough, if your parameters are loose enough to mean "any notable color difference" and not just "decidedly tan or brown", you'll get a lot more results. it might even be considered fairly common. it's used as a class/status signifier (or it hints at it) when it's like that, now that I think about it.
https://www.mangago.me/read-manga/playtime_with_hakdo/
https://www.mangago.me/read-manga/love_in_orbit/
https://www.mangago.me/read-manga/spinach_bouquet/
Haha yesss I actually do like any pairing with a darker skinned bottom even if he isn't super darkskin, for example I rlly like Ilay and Taeui from Passion where Taeui is just slightly darker, kind of like a honey tan. and I also do notice sometimes it has implications of higher status, usually with the more fair skin one being in a higher position of power but I have also seen some where the darker one has higher status, however in that case they get treated more like they're "exotic". Anyways, thank you for the extra suggestions (▰˘◡˘▰)
BLs with a "we shouldn't be doing this" kind of dynamic??? Like forbidden love y'know
Kinda incest (step bros):
https://www.mangago.me/read-manga/pond_with_flowers/
https://www.mangago.me/read-manga/the_hunter_s_one_night/
https://www.mangago.me/read-manga/semantic_error/ (mc thinks that being gay is an error)
https://www.mangago.me/read-manga/three_nights_we_really_do_it/ (They’re childhood friends)
Age gap (mc feels uncomfortable because of the age gap):
https://www.mangago.me/read-manga/projection/
https://www.mangago.me/read-manga/amber_alert/

Hiii shy/reserved older seme and cheeky or outgoing younger uke recs plsss?
https://www.mangago.me/read-manga/we_re_not_cut_out_to_be_lovers/