Elevator Pause
When pausing just before activating an elevator down, Samus will hit the bottom of the screen and stop, activating the door transition immediately instead of going off-screen before the room fades out.
If a pause is already necessary for the route, this saves about 50 seconds of real time. However, In Game Time already stops when Samus' feet hit the bottom of the screen on an elevator even without the pause, so this does not affect In Game Time.
Pausing has no effect on the door transition when going up an elevator.
This is commonly done heading to Lower Norfair Any% PRKD or PKRD after a Lava Spark, if beams are being switched off to prepare for X-Factors on Ridley, or in PKRD to re-enable Gravity Suit after a Gravity Jump. Then it's used later in these routes to re-enable beams for Tourian.
This can also sometimes be seen in 100% if no pause was needed for the Gauntlet Spark.
This strat seems to be inconsistent on Virtual Console platforms, due to an unknown emulation difference.