the doom themes, kaolin, and spacemacs themes (even though that's only 2) are some of the nicest I've found, and those are the ones I switch between the most to get rid of that weird grating feeling. Then after that, its certain individual themes, many of which taken from other places (atom-one-dark I think, any variation of molokai / monokai, the visual-studio themes occasionally) and other random themes l really like, like leuven

the gruvbox themes I also found can look really nice

still have no idea what it is that is causing that feeling, since normally I pay no attention to design and appearance (and in fact, originally I just used emacs in the terminal, and that theme felt perfect) ; I'm still wearing shirts I bought at the end of middle school, emacs is the only time I grow eyes