What makes this card particularly appealing is how well it plays in attrition-based matchups
Aristocrats decks want a zero-mana way to sacrifice their creatures, and Viscera Seer offers this, along with a valuable scry ability
But you don't need to go for the Thassa's Oracle MTG combo necessarily - usually it'll be enough to draw an enormous number of cards and play an enormous number of lands, putting you in a commanding lead
The Sliver Swarm Commander Masters Commander Deck set includes 1 ready-to-play White-Blue-Black-Red-Green deck of 100 Magic cards (2 Traditional Foil Legendary Creature cards, 98 nonfoil cards), a 2-card Collector Booster Sample Pack (contains 2 special treatment cards, with 1 Traditional Foil Common or Uncommon and 1 nonfoil or Traditional Foil Rare or Mythic Rare), 1 foil-etched Display Commander (a thick cardstock copy of the commander card with foil etched into the cards border and art), 10 double-sided tokens, 1 deck box (can hold 100 sleeved cards), 1 Life Wheel, 1 strategy insert, and 1 reference card
If you want to play multiple cards like this, you are basically adding another color to your deck
