As DI88 said, Tilidine is indeed my favourite, and I had the privilege of trying a lot of opioids thanks to the Darknet, the RC market (research chemicals) and my sister who works as a nurse in a palliative care hospital. What I can say with absolute certainty after all these years of trying all sorts of agonists, is that the potency of an opioid has zero relation to its euphoric potential INCLUDING its nociceptive potential. I had cases where a bunch of codeine was more effective at killing my past shoulder pain than superduper "strong" oxycodone. This is true for the entire non-side effect spectrum of opioid medication. That's the reason why analgetic potency is a total misnomer in my opinion, because the only thing an opioid's potency tells you is its dosage in relation to the opioid of reference, which is why we should be referring to it as dose/dosage sensitivity because this is what it actually is.
Drop the whole potency nonsense because it creates wrong expectations, both in the field of science and pain management, as well as in the recreational field (perhaps especially there). This is why doctors have to experiment so much when it comes to the right opioid agonist for their patient. It's because opioids are a wild mix. Sure, they are the most reliable drug class, but they are a wild mix (or maybe our brain chemistry is?).
Let me give you an example: most people say Heroin is one of the most euphoric opioids they have taken. Well, it turned out I didn't actually like it that much when I took it. I remember when I made the switch from Tilidine to Heroin I was somewhat disappointed. Both because its stronger sedation covered a great portion of the euphoria like a leaden blanket, as well as the fact that its duration felt less stable than Tilidine. Or how about an opposite example: Morphine. Tons of people say morph is not euphoric. I hadn't tried this agonist for a very long time because I was operating under that very same assumption. I thought that if 99% of all the people I have heard from keep saying that morph isn't worth it, then it must be true. Then one day my plug's dealer ran out of his usual palette of opioids and instead gave him a whole bunch of MS Contin 30 mg blisters, which I took ofc because that beats having no opioid high at all lol. When I dropped that pill I was amazed at how good I felt. I was weirdly sedated and motivated at the same time. It was a bit like heroin without the lead blanket feeling I described earlier.
So long story short: every opioid is unique, there is no true consensus on which one is the most euphoric. If you want proof of this, check out this thread in a swiss-german drug forum where people have made lists about their favourite opioids, ranked from most to least euphoric. Aside from Heroin, there is a great amount of interindividual variance when it comes to the perception of which opioids are the best.
https://forum.eve-rave.ch/viewtopic.php?t=37344
I think we should make a list here too, wouldn't that be fun? Lemme be the one who throws the first stone
#1 Tilidine
#2 Oxymorphone (only had one genuine pill from the USA that was not pressed fent bs)
#3 Levomethadone
#4 Oxycodone
#5 Morphine
#6 Pantopon
#7 Shire Opium
#8 Codeine
#9 O-Desmethyltramadol
#10 Tramadol
#11 Heroin (golden triangle)
#12 Heroin (afghan brown)
#13 Heroin (mexican black tar)
#14 Hydrocodone
#15 Hydromorphone (waaaay too short, otherwise it would replace Morphine)
#16 Kratom (it is beyond me how people can actually gulp down massive amounts of this awful tasting powder. Euphoria isn't always there, but if it is, it's meh)
#17 Methadone (it's just a sleeping pill)
#18 DHC (feels like the down-syndrome version of codeine to me)
#19 Buprenorphine (tried this crap for the first and last time a couple months ago)
#20 Ro4-1539 (holy mother of god, never again)
Wishlist: 1-Iodomorphine, Oxymorphazone, 14-Cinnamoyloxycodeinone, Dihydroheroin and that Tilidine derivative
@Opiophiliclab mentioned on his blog.