Discogs is the ULTIMATE way to discover new gems, from old times as recent stuff.
Discogs is more than a platform for buying records. It is the BIGGEST database for music. You have many search tools and you can easily find music by year, style, genre, label, artist, area, combine everything. You have the "Hot", "Most Wanted", "Recent" algorithms that allows you to adapt the kind of stuff you want in your result (If you need to check your classics, go for "Most Collected"). It's really powerfull.
It's not the best for listening music on it (lot of links for youtube videos are broken), but from Discogs you can then type the artist on Youtube, Bandcamp or Soundcloud.
You can make your own lists and check other peoples lists, going from one track and see familiar music by seeing numerous selections containing this song made by other users.
I've been a DJ since 10 years and I tried a lot of platforms and Discogs is the one I'm using the most.
An other way to discover music is to talk with people from your surroundings that you like the music taste and propose to exchange some music. Make some selections of tracks and send them files transfers, sometimes people will be kind and send you back some music they really enjoy.
And we can just simply start discovering new stuff from the songs we already have by checking the other projects of the artists, the labels that released the songs and have hours to spend exploring music that will really fit our tastes.