A friend of mine (years ago) had a pair of gloves with lead dust or fine shot sewn into the knuckle area. Supposedly they were police issue.
You don’t hit the hard parts with your hands.
Sap gloves as we used to call them. The “civilian version” were exercise gloves made by Saranac with weights (under a pound) across the back of the hand. A simple roundhouse usually made you the last man standing.
With knucks, saps and all of that follow the same rule as with firearms – there are good ones out there that will last for generations and maybe save your life BUT they aren’t cheap, take some training to use right and are not always easy to find some places. There are also plenty of “Saturday night specials” you can pick up at the flea market or some novelty store. Those may do you as much harm as the person you hit (trust me - I’ve seen the x-rays). So get your knowledge on first.