Variant Rule: Rate of Falling

This rule is found on in Xanathar's Guide to Everything, p. 77.
When falling from great height, character's instantly descend up to 500 feet. If they are still falling on their next turn, they descend up to another 500 feet on that turn. This process continues until the fall ends, either because the character hits the ground or the fall is otherwise halted.
In addition to the standard text of the rule, falling characters may chose to either fall immediately, or wait until the or end of their initiative.
See Also:
Variant Rule: Flying Creatures and Falling
Homebrew: Falling Damage