I've taken "LSD" blotters two times that were actually DOB. My friend had bought these at a Psytrance festival in Germany. They were sold as LSD but we quickly discovered that the trip was nothing like LSD. Extreme stimulation, amphetamine-like stimulation with extremely technical (although beautiful) visuals. He had two kinds of blotters, and the second time we took the other blotters and noticed that the effect was nothing like LSD, we were just like "fuck, not this shit again...". My friend never uses benzos but the second time we took the blotters he asked for benzos and I gave him some clonazepam which calmed he down. The stimulation was extreme and both trips felt like psychedelic speed.
After this experience, we are both extremely careful about from who we buy LSD. Fortunately there are some reliable sources.
But I guess "LSD blotters" is one of the most common scams, they can contain everything from 25I-NBOMe to DOB to DOM. Blotters are tricky and you need to know your source.
It used to be less complicated. It was either LSD, something Nick Sand invented back in BC, butyr-LSD I think or such (I'm speaking of the Canada scene, from late 90's to late '00s when I lost my contact for real LSD sheets of 100, the guy had it mailed to him straight from the hippies in BC). In the US, there was an LSD drought so people made DOC, DOI and 5-meo-amt blotter (those people should be beaten up with a plunger (5-meo-amt). I even remember photos linked by people on the newsgroup alt.drugs.psychedelics, where people laid and glued two blotter sheets on top of each other and it was 2c-e, blotter, with obvious powder , they would cut 2 pieces on top of another and there was filled as much as possible blotter with diluted 2c-E with crystals sandwiched in between. That was ridiculous.
Blotters sold online with 1P-LSD, ETH-LAD, AL-LAD etc. are fine, but for people who only deal with street LSD, seeing blotter squares larger than 1/4 inch x 1/4 inch is very suspect. Especially here, because in the late 90's/early 2000's there were oversized South Park blotters (taking on the popularity of very pure 'cid laid on south park characters) back in 2000-2001, but they were like pretty much 3/4 inch x 3/4 inch with a big obvious spot in the middle of liquid that was absorbed. They were PCP blotter and they continued (Bikers), to cut their LSD with a bit of PCP on the liquid they laid on blotter, sure there would be 100 ug of LSD but also 1mg of pcp, take a strip, go fucking mad...etc. But generally once you find THE guy, you're good. The guy who finds you call often enough to bother with. Who's blotter tastes nothing and has the correct size. It's a shame he changed cell phone number without telling me or other people I know who knew him, but he's finished his Construction technical diploma and when one works in construction, one moves around where there's work, so I haven't bothered going to his parents house, they know me, but it would be strange. Also he's the kind of guy who hates the internet and computers, he didn't even join in when the masses bothered us closet-nerds when myspace, FB etc. showed up.