street drugs i find the most euphoric would be Cocaine/Crack, IV'ed Cocaine is the most mind blowing feelings, along with smoking high quality crack, i havent tried crystal meth due to its lack of availability in my area. Ecstacy is euphoric too in it's unique way but hard to find clean cut. i once had molly and IVed 3/10ths, and it was too intense, everything was ringing, i was so dizzy i collapsed to the ground and kept yelling im going to die, im going to die,.and thought i really was, the rush of MDMA orally is so intense as it is, and for me IVing 3/10ths of molly the rush of IVing was so damn intense i couldnt think see, hear or even comprehend, the powerful overhwhelming rush lasted 4 mins, im lucky im not dead. IMO IVing heroin isnt so euphoric to me anymore since i grew out of it and now on Suboxone
as far as Pharmaceuticals, i find Amphetamines to be the most euphoriv (Dexedrine, Adderall), also a nice euphoric pharmaceutical i would say is Methadone, along with Xanax.
my main most euphoic recreational drug nowadays is just Dexedrine/Adderall and Benzo's