wish i had with a few things, i did unintentionally with the AS from bath and body works the red ones, wish i would of picked up the green and black as well. They were on for 1.50 and i purchased a bunch. I ended up gifting a few to friends without realizing they are discontinued and now i kinda regret it as the Red one was one of my favs Wish i had with Body shop original cream, that stuff smells awesome to me.
I've stockpiled injector blades. They haven't been discontinued, but they are no longer sold at my local drugstore, and who knows how long they'll be available on line.
I've got a pretty large stockpile of soaps, but am not worried about them being discontinued. Some brands, maybe, but there is no single brand that I just couldn't do without.
I bought a kilo of P160. Tried it, loved it and bought another kilo while there was still stock at ItalianBarber. That's the only product I've been able to be proactive about before it goes extinct.