I agree that Korra & Asami works well! For the understated reason, but also because it feels like they actually bond over meaningful experiences. So many uninspired romances are just "well these two are the leads, so...*shrug*". Giving the characters chemistry and history together is huge.
I adore close friendships in media. We don't get them nearly enough -- and whenever they do happen, the romance speculation is inescapable (looking at
you, Sam-Is-Gay-For-Frodo jokes). One of my favorites is Gunnerkrigg Court.
Spoiler: ...can you spoiler a spoiler? Gunnerkrigg Court
Show
Annie and Kat are best friends growing up, and even though one of them is revealed to be bi (lesbian? it's not 100% clear) further into the storyline, the comic never once even toys with the idea of romance between these two. I really appreciate that celebration of close friendship...plus, the series still doesn't erase WLW romance to do it! They have a lesbian/bi(?) main character in both a committed relationship and with a close female friend at the same time.