Collision layer
A layer-and-bitmask system that controls which objects are even allowed to collide with one another.
Not everything should hit everything. With collision layers each object is tagged with the layer it belongs to and the layers it reacts to, often as bitmasks: the player's bullets hit enemies but pass straight through the player, and pickups only fire a trigger. A collision matrix states which pairs of layers are tested against each other.
Beyond preventing unwanted interactions it is a performance win — pairs that would be ignored anyway are culled in the broad phase instead of being tested in detail. Unity's Layer Collision Matrix and Godot's layer/mask fields are typical implementations.