They arent tied to any specific color in the color pie, which means, technically , any deck can use them
This set acknowledges the popular high-end Commanders of cEDH and delivers up a platter of the most popular as Final Fantasy characters
Even today, I have to assume it's a tremendously popular card, as it keeps showing up in sets, Commander included, and has about nine different printings, including a Secret Lair option
Krenko, Baron of Tin Street Goblins are known for their numbers, and Krenko, Baron of Tin Street gives you a way to produce goblins and put +1/+1 counters on them
Market is around $25, and that seems to be the price you're looking at right now as well