Not sure if anyone's brought these up, but I've found a bunch of bootleg minifigures on eBay. There are quite a few for Spider-Man, a lot of which are costumes and designs that haven't been released officially by Lego.
Some of the minifigures in the picture are official. The two Spider-Men from the original Spidey movies, the Civil War/Homecoming Spideys, Scarlet Spider, Spider-Woman, the Ultimate Spider-Men, and Iron Spider-Man are all official. The rest are bootlegs, but for the most part you really couldn't tell. The only one that's somewhat obvious is Spider-Boy (guy with the glasses and jacket), and that's only if you could touch the figure. The paint they used for the designs is raised.
The rest are all of surprisingly good quality and if, like me, you just have them on display they're totally fine.
I've also got non-Spidey knockoff minifigures.
There's Gwenpool, who, if you look at the chest piece, seems to have sides that are a bit caved in for some reason. No other minifigures I have are like that.
Also Lady Deadpool and Scotty from Star Trek. They're of pretty good quality.
Just wanted to share these, since it seemed relevant.
(Sorry if the pictures are rotated oddly. I have no idea why that is.)