My favorite genre! SoL often crosses into other genres, so my answer would probably vary depending on how open we can be!
On the Romance side there's just sooo many I love- My Dress-Up Darling, A Sign of Affection, Horimiya, You and I are Polar Opposites.
For music - K-On and most definitely Sound Euphonium (in my top 3 all time)
Topic-based- DIY, Ruri Rocks, Yuru Camp, New Game
General randomess - Saiki K, YuruYuri
If I had to pick just one it would be Sound Euphonium. Absolutely beautiful series đ”