Since 8tracks is constrained to be legal, you aren't allowed to know exactly what I've programmed. But the following names could be relevant: John Adams, John Cage, Fred Frith, Jonny Greenwood, Joan Jeanrenaud, Gidon Kremer, Paul Lansky, Arvo Part, Radiohead, Sonic Youth, Edo de Waart, and William Winant
8tracks legal q&a e.g. An objective of the compulsory license is to ensure that a listener's experience is similar to traditional radio and essentially non-interactive (i.e., you can't hear a specific song when you want it), so as not to substitute for music purchase.
Update: 8tracks may have solved the legal problems but there may still be some operational bugs -- I can't seem to play through the entire mix.
Update #2: It is working now for me.