A triggered ability that has triggered but is waiting to be placed on the stack is controlled by the player who controlled its source at the time it triggered, unless it’s a delayed triggered ability. To determine the controller of a delayed triggered ability, see rules 603.7d–f. See also rule 603, “Handling Triggered Abilities.”
July 3, 2020 · Core Set 2021
An emblem is controlled by the player that puts it into the command zone. See rule 114, “Emblems.”
July 1, 2012 · Magic 2013
In a Planechase game, a face-up plane or phenomenon card is controlled by the player designated as the planar controller. This is usually the active player. See rule 901.6.
February 1, 2012 · Dark Ascension
In a Planechase game, a face-up plane card is controlled by the player designated as the planar controller. This is usually the active player. See rule 901.6.
February 1, 2010 · Worldwake
In a Vanguard game, each vanguard card is controlled by its owner. See rule 902.6.