Dr. Doom Through the Ages set

Clockwise from the front: Secret Wars Doom, Unthinkable Doom, Gypsy Doom, and Doom 2099.

Secret Wars Doom shamelessly uses decals from DST's control art. His arms and legs are from the Villains set Doom, with the boots repainted. His hood is from the Spectre. Unthinkable Doom has a modified Doom cape, a Spectre hood, Star Trek ankle cuffs, and knee pads cut from some random piece of plastic. His face and chest are decals. Gypsy Doom also has face and chest decals. His cauldron is a repainted Spider-Man mask. Doom 2099 has a modified Bison cape, a Spectre hood, and chest and face decals. His spikes are cut from the tips of Green Arrow's quiver.

Gypsy Doom and Unthinkable Doom are based on their appearances in the Unthinkable story, which started in Fantastic Four #497 (or Vol. 3 #67 if you prefer). It is easily my favorite FF story from the last 10 years. If you haven't read it, you are missing out on a great Doom story!