1

Lose an Eye. You have disadvantage on Wisdom (Perception) checks that rely on sight and on ranged attack rolls. Magic such as the regenerate spell can restore the lost eye. If you have no eyes left after sustaining this injury, you're blinded.

2

Lose an Arm/Hand/Fingers You can no longer hold anything with two hands, and you can hold only a single object at a time. You lose the ability to perform somatic gestures with that hand. Magic such as the regenerate spell can restore the lost appendage.

3

Lose a Foot or Leg. Without support, you are considered prone and cannot move.

If you have a cane or crutch or other prosthesis, your speed is halved. You fall prone after using the Dash action. You have disadvantage on Dexterity checks made to balance. Magic such as the regenerate spell can restore the lost appendage. An advanced prosthesis can prevent these disadvantages.

4

Limp. Your speed on foot is reduced by 10 feet. You must make a DC 10 Dexterity saving throw after using the Dash action. If you fail the save, you fall prone. Magical healing removes the limp.

5-6-7

Internal Injury. Whenever you attempt an action in combat, you must make a DC 15 Constitution saving throw. On a failed save, you lose your action and can't use reactions until the start of your next turn. The injury heals if you receive magical healing or if you spend ten days doing nothing but resting.

8-9-10

Broken Ribs. Whenever you attempt an action in combat, you must make a DC 10 Constitution saving throw. On a failed save, you lose your action and can't use reactions until the start of your next turn. The injury heals if you receive magical healing or if you spend ten days doing nothing but resting.

11-12-13

Horrible Scar. You are disfigured to the extent that the wound can't be easily concealed. You have disadvantage on Charisma (Persuasion) checks and advantage on Charisma (Intimidation) checks. Magical healing of 6th level or higher, such as heal and regenerate, removes the scar.

14-15-16

Festering Wound. Your hit point maximum is reduced by 2d8. The wound heals if you receive magical healing of at least triple the hit-point maximum you’ve lost. Alternatively, someone can tend to the wound and make a DC 15 Wisdom (Medicine) check once every 24 hours. After 3 successes, the wound heals.
It leaves a minor scar.

17-18-19

Minor Scar. The scar doesn't have any adverse effect. Divine healing or magical healing of 6th level or higher, such as heal and regenerate, removes the scar.

20

Fuck that. you regain 1 HP and if the situation allows it can use your reaction to immediately make an attack or cast a cantrip spell. Conditions such as fear or paralyzed end.