I'm not sure why you'd want the most sought after. Do whatever you like. *we aren't here to help you sell drugs...........
BUT MDMA is probably the most sought after. MDPV, if you and your friends like tweaking and dangerous chemicals, is pretty good. 4MMC, lots of people love it, but it's addicting. Cocaine, well it's not the 80s.. But plenty of people still like doing it.
They're drugs, they're all sought after.