My favorite anime isn’t always my top rated, Phantom World is one of my favorites but I didn’t rate it above 9.0, while there are an anime with 9.0+ rating but it isn’t one of my favorites, so I think you should let the user to customize it theirselves, ie. a love button in an anime’s page like Kitsu/AniList.

Like what you guys did with liked characters, I think favorites can have a separate tab on the user’s profile or just merge the two (I said this in the GitHub thread probably) and rename the tab to ♥ Favorites, while the two are in separate sections (like the Forum tab on users’ page, with a “Post” and “Thread” subtab below it).

To make it pretty looking, it can be implemented the same way as with ♥ Characters, but with anime (covers).