Last.fm - Music tracking site: tracks what music you listen to on multiple platforms, including both spotify and itunes + many others. It gives you a pretty comprehensive look at all your listening habits (Spotify wrapped whenever you want, basically), so just create an account and leave it to do its thing.

Sitting on Clouds - VGM/Anime rips: my current go-to for most soundtracks. Downloads are hosted on mega and mediafire for really quick and simple downloads, plus you don't need to crawl through hundreds of ad-filled link shorteners.

Gnoosic - Music discovery site: type in 3 bands you like, and the site will recommend you other artists based off your picks, and often tends to give you stuff that you likely wouldn’t have found through other methods.

Chartmymusic - Album Collage Generator: a fun little webtool that creates a collage of your recent album listens, with options both for Spotify and Last.fm.

Spotify to MP3 - Track searching site: grab single tracks hosted on spotify. May require some manual metadata editing.

KHInsider - VGM rips: a good backup for when you want to find a really obscure ost, though do note that you can't mass-download entire albums, so I tend to personally avoid going here when I need a 3+ hour soundtrack download.

Zophar’s Domain - Retro VGM Rips: self-explanatory; just a site that hosts a good collection of video game soundrips, with a focus on the earlier generations.