If you're wanting bespoke abilities that tell you exactly what they do, then A5E maneuvers might be what you want. If that's not quite doing it, there's the Mighty Deeds option I posted above. Another article I found today that I think is kinda genius in how simple it is is here: Combat Maneuvers, The Easy WayGive them a cup of tea and a biscuit. (That's a cookie for our American Cousins.)
Thinking a bit deeper... I do like to have options for any character I play.* So I'd give them manoeuvres and such. Like maybe some sort of feats that give them more options and special abilities. Basically I'd just re-invent DND 3e. Or maybe PF 2e.
*This lack of interesting options is where 5e leaves colder than a dead halibut on an ice flow.