If youre looking for a powerful red dragon, you still cant go wrong with Goldspan Dragon ($55)
Then a massive 7 mana needs to be spent to level up again and this time you can force your foes to lose life equal to the lost life this turn in your end step, which I've never seen anyone get, but it's a double win con, card draw, and graveyard filling in one card, so it can play nicely in graveyard adjacent brews like reanimation and recursion, with the aforementioned Aristocrats and Sacrifice brews as well as in decks with a lot of flashback
Helm of Kaldra The original Mirrodin block pieces of Kaldra are a fun trio of equipment, but the strength of the finished Helm of Kaldra is a bit lackluster compared to modern day Magics payoffs
I hope Wizards continues to tweak them as I havent encountered any truly egregious sealed pools, but I do hear the discussion about how Play Boosters have increased the randomness of limited gameplay in negative ways
In another, you are bound to find something
Living Death Living Death (no, not Living End) is a 5-mana sorcery that basically swaps the creatures in play with the creatures in graveyards