You ever heard of Every Noise at Once? You can search for an artist, see the genres they belong to, and then look for artists nearby in 2D musical space (oversimplified a bit to be fair) within that genre. I've found it's generally pretty accurate, and I've found plenty of new artists this way.
Unfortunately no longer being updated, but still has a fantastic backlog of new-ish artists.
Unfortunately no longer being updated, but still has a fantastic backlog of new-ish artists.