Shifting Combatant
A new D&D beyond drop included a feat Shifting Combatant with this ability
> Domino Strike. When you hit a creature with a weapon and activate the Push mastery property to push that creature into a space occupied by a Large or smaller creature, you can force the creatures to collide. Each creature must succeed on a Constitution saving throw (DC 8 plus the ability modifier of the score increased by this feat and your Proficiency Bonus) or have the Prone Condition.
I always thought this is how push worked by RAW even without a save based on this rule.
> You can’t willingly end a move in a space occupied by another creature. If you somehow end a turn in a space with another creature, you have the Prone condition (see the rules glossary) unless you are Tiny or are of a larger size than the other creature.
So if a player pushes a monster into another monster both monster fall prone at the end of the turn.
Have I’ve been unintentionally buffing push mechanics at my table?