"Pay 1 life, Sacrifice this land: Search your library for a [basic land type(s)] card, put it onto the battlefield, then shuffle." A fetch land in MTG is a land that lets you sacrifice it to search your library for a land with the specified land type(s) and put that land onto the battlefield
Combat damage is a recurring theme among rogue commanders, so filling your deck with combat damage payoffs, effects that can make your creatures unblockable, and other evasion abilities like flying, skulk, and menace are extra useful
There are lots of Eevees featured in the Team Gallery subset but like Evolving Skies, Umbreon is usually the most requested card that comes out on top
Losing the Game The ways you can lose the game don't change, but what happens when a player loses is very different
With Marneus, this not only generates massive card advantage but also provides strategic utility by copying impactful creatures like [[Thassa's Oracle]] or mana dorks