I have done that.You could have any existing or new weapon mastery be able to be applied to a feasible weapon. All pole like weapons could topple, all heavy weapons can push, etc.
or Brutal weapon.An example could be “Skewer” where you deal extra damage to Prone targets, and it can only be applied to piercing and slashing weapons.
“Crush” could apply to bludgeoning weapons and have them give -1 to a target’s AC that lasts until the start of your next turn.
I've occasionally included various special techniques and abilities that can be learned by martial characters. For example: from rare books, from retired or legendary heroes, from spiritual personifications of battle (like Valkyries or Furies or einherjar), from the spirits of legendary warriors, from obscure knightly or monastic orders.So there's always been ideas about making custom spells, but what what about custom martial maneuvers?
Any suggestions on how to pull that off?
Really like your whole post here, but especially these.option for Graze and Topple:
Topple, no saving throw but you need to beat AC by 5 to activate. Save time on rolls
Graze: if you miss AC by 5 or less, deal minimal damage of attack.
still makes boosting AC/accuracy a thing.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.