[JimmyBiscuit]

There were multiple, I think they were called 1p-LSD, 1cp-LSD, 1d-LSD, 1v-LSD and currently you can still legally buy 1S-LSD. Its a bit of whack-a-mole with the lawmakers because there isnt a blanket ban, only ever the specific chemical gets banned. Although stuff got quite a lot more expensive with every iteration.

[Nursie]

Prior to those there were LSZ (lysergic acid dimethylazetidide) and AL-LAD doing the rounds in the UK. Very briefly PARGY-LAD too.

1P-LSD was something of a breakthrough IIRC (never tried it but I was still following the scene at that point) because unlike the others it is a pro-drug for LSD, being quickly metabolised to the parent compound, rather than a different but closely related compound as the others were.

Never heard of the rest of those though! I stopped paying attention sometime around then.

[s3krit]

Not quite the specific chemicals anymore. As I understood it, when they outlawed 1v, the legislation was changed to also consider the weight of the molecule. Ok fine, still whack-a-mole, it just took the clandestine chemists slightly longer to figure out what mostly inert structures they could add to the LSD (though not actually add, since that would mean they were at some point making LSD, which is illegal) that would be cleaved off metabolically so you end up with LSD in your system