I know of one, that I am proudly a member of, since a long time, but they ask for certain proofs, not anybody can get in, they weren't always that way, but one time some H using junkie was found dead and there was something in the mail from them and that made them tighten up everything, a lot, some years ago. Not really a PPE, more of an RC vendor, with some pharmaceuticals in their pure powder form. If you went to college/uni for almost any science based degrees, it should cover it. But I won't link to them right here, sorry. There's a couple others that I don't use much anymore and they have the same very severe restrictions as to whom they let in. And weed legalization is an amazing and basic human right that was great to obtain, but that only created very zealous, angry customs agents, for "cutting" on their work load, same with federal/provincial cops if you live in a province where you have your own Provincial Police and the mounties are never around. They seize stuff that's non-scheduled, stuff in schedules low enough that do not apply to the analogue laws, say schedule IV, where a compound has to be explicitly mentioned. Of course, one is free to fight the seizure by the CBSA, but really, losing 50 dollars worth of btc is not worth the money one would need to lawyer up for. So they are just being asses there since cannabis legalization, I do tons of overseas orders, mostly just media, physical (I'm old school, plus, you never know when the internet will delete what you took for granted, that's why I make double layer blu-ray archives of all my downloads monthly, also on external hard drives and usb keys, but those can break or in case of aurora borealis (or worse, something caused by the psychopaths ruling this world), that grills all data on those, but not on BD-R's, DVD-R's etc.
I always knew cannabis legalization was gonna be a double edged sword. meh. US based vendors that shipped interesting/proven to be useful compounds to Canada all stopped doing so, afaik, by that timeframe too, early 2018.