Way of Judo

Judo is a martial arts from the east focusing on self-defense. The objective of  judo is to throw an opponent, immobilize them with a pin, or force an opponent to submit with a choke. While striking them down them down.

The Art of Grabbing

At level 3 You gain expertise in athletics and acrobatics and can use acrobatics or athletics to grapple. To grapple you must forgo 1 of your melee attacks and beat the opponent athletics or acrobatics roll. Or you if you land an unarmed strike you can spend 1 Ki and grapple the creature immediately.

Bōei: If a creature tries to grapple you and you win the contest you can spend a reaction and grapple it instead.

Kata: Once per turn you can deal damage to a creature grabed by you equal to your unarmed strike.

You can now grapple Large creatures even if you are small.

The Art of Throwing

At level 6 You can throw a grabbed creature 5 feet away at the cost of 1 Ki, when the creature lands it lands prone and takes xd6 bludgeoning If it collides with any creatures that are equal size to it or smaller the creatures also land prone and take xd6 bludgeoning. This ends your grab.

The damage is size dependent:

Small 1d6, Medium 2d6, Large, 4d6, Huge, 6d6, Gargatuan 8d6. 

The Art of Holding

Level 11 As an action you can spend 1 ki to chokehold a grabbed creature (if the DM thinks the creature can be chokehold) the grabbed creature has disadvantage on attack rolls against you and can't speak during your chokehold. The creature must make a strenght saving throw gainst your Ki save Dc for you land your chokehold. Your chokehold ends if the creature escapes your grab or you get unconscious.

Or you spend 1 ki and your action to pin a grappled creature this restrains it but you also count as restraint during it. The creature must make a strenght saving throw gainst your Ki save Dc if it fails you land your pin lands. Your pin ends if the creature escapes your grab or you get unconscious.

You can now grapple huge creatures.

Judo Master

At 17th level you become a master of the martial arts and can power yourself up, by spending 3 ki you empower yourself as an action for 10 minutes. During that you can treat every roll of athletics or acrobatics as a minimum of 20. Take half damage from everything while grappling and can grapple gargatuan creatures.