Recover is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Return target creature card from your graveyard to your hand. Draw a card.

How it works : Recover

Original English text — Wizards of the Coast / Scryfall

No additional ruling has been published for this card.

Interactions with other cards

These cards' text mentions Recover.

Circle of the Land Druid

When this creature enters, you may mill four cards. (You may put the top four cards of your library into your graveyard.) Natural Recovery — When this creature dies, return target land card from your graveyard to your hand.

Garza's Assassin

Sacrifice this creature: Destroy target nonblack creature. Recover—Pay half your life, rounded up. (When another creature is put into your graveyard from the battlefield, you may pay half your life, rounded up. If you do, return this card from your graveyard to your hand. Otherwise, exile this card.)

Grim Harvest

Return target creature card from your graveyard to your hand. Recover {2}{B} (When a creature is put into your graveyard from the battlefield, you may pay {2}{B}. If you do, return this card from your graveyard to your hand. Otherwise, exile this card.)

Icefall

Destroy target artifact or land. Recover {R}{R} (When a creature is put into your graveyard from the battlefield, you may pay {R}{R}. If you do, return this card from your graveyard to your hand. Otherwise, exile this card.)

Controvert

Counter target spell. Recover {2}{U}{U} (When a creature is put into your graveyard from the battlefield, you may pay {2}{U}{U}. If you do, return this card from your graveyard to your hand. Otherwise, exile this card.)

Resize

Target creature gets +3/+3 until end of turn. Recover {1}{G} (When a creature is put into your graveyard from the battlefield, you may pay {1}{G}. If you do, return this card from your graveyard to your hand. Otherwise, exile this card.)

Sun's Bounty

You gain 4 life. Recover {1}{W} (When a creature is put into your graveyard from the battlefield, you may pay {1}{W}. If you do, return this card from your graveyard to your hand. Otherwise, exile this card.)

Krovikan Rot

Destroy target creature with power 2 or less. Recover {1}{B}{B} (When a creature is put into your graveyard from the battlefield, you may pay {1}{B}{B}. If you do, return this card from your graveyard to your hand. Otherwise, exile this card.)