First of all, it's slipperier than you might imagine at first: Too many great blockers simply can't block it at all, such as Commander Eesha, Silklash Spider, Wall of Denial, Will-o'-the-Wisp, Fog Bank, Mogg Maniac, Typhoid Rats, and many other great bodies
The commanders on this list are almost exclusively multicolored, with a chunk of mono-red options and a non-red commander here and there
While its on the battlefield, your opponents artifacts and enchantments cost two more mana to cast
4 Koth Of The Hammer Doubles Your Current Red Mana Koth of the Hammer is a red Planeswalker from Scars of Mirrodin
For the uninitiated, Commander is Magic: The Gathering's most popular format, and can be enjoyed by much more than just two players (my group regularly plays with six)
Gilgamesh, Master-at-Arms Gilgamesh, Master-at-Arms costs a lot but makes up for it by freely putting equipment onto your battlefield