EDM has been the soundtrack for MDMA since the beginning. Psychedelic rock is inseparable from LSD. But why stay there... We have non-EDM soundtracks that rock our world on MDMA, and EDM that pairs perfectly with LSD.
Rock, Psychedelic, etc.
MDMA made us "understand" EDM. LSD made us understand Obscured by Coulds. Rock, new and old, is revealed by LSD. Nothing like hearing details you've never heard before on that song you've listened to a hundred times.
Early Techno (think Kraftwerk) feels pretty epic to us. Ambient and chill wave are always interesting too.
World music, acid jazz, soul, new age, whatever matches the mood.