You can see examples of the cards on the Wizards of the Coast blog
For instance Download card art for the alts you want to display: Update: A helpful person has collated all of the current alternate arts
Lightning Greaves and Swiftfoot Boots are obvious includes, but instants like Blacksmiths Skill, Deflecting Swat and Wild Ricochet are essential to protecting your King
Cavalier of Flame This Cavalier had a stint in Standard and Pioneer as an important piece of Fires of Invention decks
For certain Commander players, immersion-breaking power isn't worth it, even if these decks can win them many games with the overwhelming power of artifacts, +1/+1 counters, and living semi trucks that roll out and attack for lethal.
You can then choose a Forward controlled by your opponent, and if the cards cost is equal to the cost of the card discarded by the extra cost, you can break it and draw a card