Sometimes a new one pops up as a one-off promotional card, but that doesn't really count
This card is not going to come cheaply, with MP copies still floating around the $50 range, so you'll need to settle for a damaged copy if you're trying to stick to a smaller budget
The update from Wizards of the Coast not only includes the ban of certain MTG cards, but it also announces the unban of some , bringing them back into legal play
You could discard it to pay a cost, because a spell or ability tells you to, or because you have too many cards in your hand during your cleanup step
That being said, the rewards may not be worth the waste if you don't intend to use the card or hope to save up for a rarer one
Card not found from Scourge (2003) is an oddity on this list as it requires a creature to work properly, but in the right deck it might be quite strong