You can also win by drawing out your library, using Jace, Wielder of Mysteries' effect, or Laboratory Maniac's effect
Some believe that Marina is the one person who would be able to defeat Valgavoth, but no one dares try to make her see the House as it really is, as disturbing her causes hordes of cellarspawn to converge on her location, killing all others in the vicinity so that she can maintain her ignorance of what the House has become
However, you must also sacrifice a creature to pay for the spell, and it generates three red mana
That might sound innocent, and looks like it when it just copies a Sky Diamond, maybe an Idol of Oblivion for card draw
They generate overwhelming advantage quickly, but if the opponent keeps fighting they can be overcome
It doesnt have complex mechanics, confusing interactions, or clever tricks