One of my favourite cards is probably
Cabal Therapy. Rn I think I own about 12 copies, 4 are Chinese and they're pretty sweet. I opened it from an actual Judgement pack way back when I was a kid and have kept it. I used to run it along with
Duress in my R/B Nightmares deck when
Torment was in standard. I have played it in many a mono-black deck and I love how it interacts with
Mishra's Factory in my build of
Pox (1 colourless mana to activate the factory, flashback
Cabal Therapy). I play it in Storm because it's really powerful and combos with
Gitaxian Probe to eliminate the guessing game. I play it in
Dredge because it's a house. Strip yr opponent of a card, fart out a couple of 2/2 zombies and do it again. I think
Dredge might be the best
Cabal Therapy deck ever and I just love this card and I will find an excuse to play it whenever I can.
I think after that card I really like
Lightning Bolt. It's the best Instant ever. The design is so
simple, powerful and fun. I own a zillion copies of that card and I collected only Lightning Bolts exclusively for a while. I enjoy
Remand and
Eternal Witness, because they represent this kind of weird card advantage that puts the "Huh?" look on your opponent's face every time. And lastly, one of my favorite cards of all time is
Fallen Angel. Time has not been kind to
Fallen Angel, but for the low, low price of a creature, you can
Unholy Strength a 3/3, flying, black, angel. I love it from a design aspect (this sad angel who fell from up above and starts making everyone sacrifice all the things because she's fallen and sad) and from how I used to just play it in all of my decks. Thanks for reading!