the Incredible Hulk
Stan Lee originally intended the Hulk to be coloured gray, believing that "gray would be a heavy, dramatic, sombre colour, in keeping with the melodramatic mood we wanted to establish." However, initial copies of the first issue showed that the printers had a difficult time maintaining the gray colour, and the decision was made to change his skin to the more familiar green. Until 1986, any and all reprints featuring the origin story would depict the Hulk with green skin, until writer/artist John Byrne would incorporate the original gray colouring into canon in The Incredible Hulk #318. This was around the time these pins were being produced, hence both green and grey Hulk.
Made in 1988. Planet pin #034
Made in 1994. Planet pin #341
Made in 1993. Planet pin #317. Several characters appeared in Santa hat's - the Thing, Punisher, Spider-Man, Venom and the Wolverine.
Made in 1991. Planet pin #177
Made in 1994. Planet pin #333
Made in 1992. Planet pin#218
Made in 1991. Planet pin #207
Made in 1990. Planet pin #107
Made in 1991. Planet pin #Art1-e5 Kirby Hulk. Part of the limited edition, boxed set "Jack Kirby Collection Vol.1". There never was a volume 2.
Made in 1990. Planet pin #132
Made in 1989. No Planet pin #.
Made in 1988. Planet pin #064. One of my favorite pins.
Made in 1990. Planet pin #125. Interestingly this has "Hero vs Hero 82" printed on the back with the date and copyright - I brought some pins from eBay and the seller quoted the pin number - when I asked about it he said it was the on a list of the pin designs produced i.e. this is the 81 pin design Planet made. He wasn't able to give much more information than that.