In a given game, you only see so many cards. Most games, a player is likely to see their starting seven, their first card drawn, and their card each turn for roughly eight turns. In a medium-to-long game, you might see 15 cards, or 15% of your deck. If you have 10 copies of a card or effect, you’ll likely see one, maybe two in a game. If it’s something you really need to see, like a win con, you want to increase the amount of cards you see. This can be done any of a few different ways:
These cards increase the amount of cards you see over the course of a game, but, without help, they don’t increase the amount of cards you have access to. Because you are spending a card to cast the spell but not gaining access to more cards, they are considered to be card disadvantage.
Rummaging-
Rummaging is when you discard cards before drawing cards. This is a typically Red ability, and works well when you want to aggressively dig through the deck to find cards that aren’t in your hand. It also works well when the cards in your hand are still useful in the grave, like Faithless Looting’s Flashback ability. Cards like Tormenting Voice have been heavily printed recently.
Looting-
Looting is kind of the antithesis to Rummaging: it draws the cards first, and then makes you discard the same amount of cards. As a result, you have access to more information before deciding what to draw and can protect cards in your hand. This works better when you want specific cards in the graveyard, like for meeting Delirium requirements, setting up Madness spells, or binning a big spell to reanimate later. Cards like Frantic Search and Merfolk Looter help these plans.
Regrowths-
Like Rummaging and Looting, Regrowths spend a card but don’t put you up any material. Instead, you spend a card to get a card back, sometimes with stipulations. All three require setup: Rummaging and Looting require cards in hand and Regrowths require targets in the grave. Regrowths and Raise Dead effects work well with spells that put cards in the grave for an early advantage through Bloodrush, Channel, or Cycling.