Bocchi the rock
Horimiya
The Pet Girl of Sakurasou
FLCL (not really wholesome, but short)
Yuri on Ice
Lycoris Recoil

Watch Summer Time Rendering, basically everything you ask for

No idea what you consider as "super heavy", but maybe alt. and the last martyr could be something for you. To Octavia is also pretty good if you want to try melodic metal

Summer Time Rendering