A random common from an old set may still be worth very little, while a rare land, iconic spell, or Reserved List card from the same era could be worth a serious amount
Notable Cards, Reprints, and $$ The reprint value is reasonable but not too noteworthy
Midnight Reaper + Friends There are actually a ton of these little card advantage dudes, including Midnight Reaper, Liliana's Standard Bearer, Headless Rider, Archghoul of Thraben, and I could probably go on but Ive got some dead ones nipping at my heels
Intellect Devourer Intellect Devourer may not be the strongest card, but it can steal cards from your opponents hand and play them for as long as they remain exiled
As for the other five types, Fighting, Dragon, and Colorless have 1 card each (though the Fighting-type uses only Lightning energy to attack), while Fairy and Steel are absent