Drawing and going first
When there are more than two players/teams.

103.7a In a two-player game, the player who plays first skips the draw step (see rule 504, “Draw Step”) of his or her first turn.
103.7b In a Two-Headed Giant game, the team who plays first skips the draw step of their first turn.
103.7c In all other multiplayer games, no player skips the draw step of his or her first turn.