mtg return target card from your graveyard to your hand A-Graveyard Shift · Streets of New Capenna (SNC) #A-81 · Scryfall Magic: The Gathering Search Eternal Witness [Modern Masters]

This has not been announced for Gateway , however

This allows these lands to be tutored at any time, smoothing your next turn right before your opponents turn ends, making it easier for you to react to what they just played

Playing a Land simply means placing it from your hand onto the Battlefield (aka the area of play, open to the view of all players)

(Exile cards from the top of your library until you exile a nonland card with mana value 5 or less

This is huge because there are plenty of excellent Floodborn characters such as Beast Tragic Hero that wouldnt be played with shift (paying less ink to play on top of an existing Beast character) as the cost of playing it normally was easily justified with the power of the character