The MS-Contin 60mg's were amazing, the come up on those was magical. I used to crush them up and boof them after dissolving in some water. The OG Roxicodones were out of this world, but we dont have the pleasure of copping those anymore. Insufflating fentanyl totally surprised me, and had a nice binge on them for a while living in LA, went great with good blow. I got up to taking 420mics of Fentanyl, and actually came off of it using some spiked Kratom (sprayed with o-desmethyltramadol or U-47700). I could take one gram and my eyes were more pinned out than on fentanyl, made my feces so hard I had to dig it out with a knife (ahh opiate life lol).
In regard to Kratom, as a long-time user of all manner of opiates (most of what you listed in the poll), including a 10-year heroin addiction amidst the morphine and oxy abuse, I can tell you there are some gems in the Kratom realm that deserve your attention. Recently I had some 50:1 and 125:1 extracts that were better than Oxies. Truly amazing what mitragynine and 7-OH-mitragynine can do. Look at the studies of how powerful those compounds are. The 7OH variant has been tested in the lab to exceed the potency of morphine, just to give you an idea.