Gitaxian Probe + Mishra's Bauble Let's put it this way: A cantrip that you can pay for with life rather than mana, and tells you what your foe's up to, is so fundamentally broken that Gitaxian Probe is banned in Modern and Legacy, and it's also restricted in Vintage, where it's no stranger to top-tier decks
The Archon is a 3/2 with a highly useful protection ability
The cost is 1R, but players have to sacrifice Furnace Skullbomb too, which costs one mana of any color to put on the battlefield
Paying 2 life for an untapped land or nothing to have it come into play tapped feels like the perfect balance
Monument to Endurance This is such an interesting artifact for decks that discard a lot of cards and one that I think brings a lot to the table for commanders such as Rielle, the Everwise or Nekusar, the Mindraker as a way to get value out of discarding cards
It could also turn a game if not countered, depending on the card in play you chose to take