Whenever Glint Raker deals combat damage to a player, you may reveal that many cards from the top of your library
If we already have a board full of Servos and Clues, it's usually better to put the counters on Marionette Master, which means every time a Servo or Clue dies, we'll drain our opponent for four (or more, if Angel of Invention is giving everything +1/+1)
Planeswalkers often benefit from damage prevention because it stops your opponents from attacking them effectively, buying plenty of time to ultimate them and get a shiny emblem
Honorable Mention #4 (#12 Overall) - Darksteel Monolith Check out this fun eight-drop indestructible rare
Legality depends on the tournament format -- Jecht, Reluctant Guardian // Braska's Final Aeon can be legal in some formats and banned or restricted in others
A set designed for 2 vs 2 games