Forget tags in an era where broke rappers will find a way to rap over whatever they want so your best bet is to find some artists (who have a 9-to-5 that ain't minimum wage) and build with 'em.
A lot of rappers on youtube BUT alot of BROKE rappers on youtube too. A lot of them don't want o pay either and will download/convert the video to audio and use. I got the purchase your tracks tag in most of my recent beats.