I agree with a lot of the answers already here and this days I feel like I'm really into vns music so well, long answer incoming ig.
I'm really into Elements Garden (Utapri has so many good songs...), MANYO, Shikata Akiko... And I didn't know pc Hana Awase had instrumental OP so now I'm curious, I love the vocal ones (I'm more fond of the Switch ones but PC vocal ones are also fun).
I guess, to not repeat some of the already mentioned, Love Solfege stuff is something I adore to listen (specially Shinigami to Shoujo OP is a big favorite of mine, but all Matsumoto Shin'ichirou stuff is just so good, I'm happy he worked in so many otomes and would love to have him in future projects...). Also Hanayaka nari (...) EDS for the Switch ver have some really good songs. I'm particularly fond of Shimotsuki Haruka duet with Oda Kaori, (composed by myu) "Koyoi, Sameyaranu Yume o".
I love rejet stuff made by PROCYON STUDIO (Black wolves saga, Ken ga Kimi) I really like lasah voice but also the use of orchestra in the bgm and the violins they use in all vocal songs are something I really enjoy. Even MIKOTO compositions (Diabolik lovers, for example) are really fun to listen, I like the edgy touch they have.
Someone mentioned Virche and I have to say that I also loved a lot both first game and fd songs. I specially like aya songs and also her as a composer. She composed all the eds (and even singed some) for Chouchou Jiken Lovesodic and I really like those songs.
Also this days I'm starting to enjoy a lot some TAKUYO stuff, I really loved already Sweet Clown OP but now I'm enjoying a lot all the Lambsoars and flaque songs they used in their games.
In terms of BL I really like Itou Kanako and ZIZZ studio so NITRO CHIRAL in general had a lot of songs I enjoyed. I'm not the biggest I've sound fan but "Under the darkness" is a really catchy song, ngl. And I guess in more obscure things, maybe, Suzuka Yumi has a really good voice and interesting way of composing I really like for example Ariard OP.
Anyway, sorry for the long answer!