Mp3Boo is i would consider a gem in the search engines listed here. The UI is just amazing with pinterest like layout. All of the songs are categorized into albums and artists totaling it has around 28417 mp3 albums, 371493 tracks, 20606 artists and more added every day. All songs are further categorized into hundreds for genres and charts which should enrich your music discovery. Started in 2014 it became too popular and now being blocked in UK. Given the rich user experience, it is worth the try!!