5e Rangers are often seen as weak. They do get Fighting Styles at level 2, which gives some potential design space for a boost. I came up with the following:
Ranger Fighting Style - Favoured Foe: Once per turn, you can deal an extra 1d6 damage to one Favoured Enemy you hit with a melee weapon or ranged weapon attack, if you do not have disadvantage on the attack roll. Damage increases +1d6 per 4 Ranger levels.
Ranger Level Favoured Foe Damage
2 +1d6
6 +2d6
10 +3d6
14 +4d6
18 +5d6
So it's basically a half-strength sneak attack, which I think fits with the Ranger's placement between Fighter and Rogue in design.
BTW I let Beastmaster Rangers order their beasts as a bonus action, so this is useable by them.
Ranger Fighting Style - Favoured Foe: Once per turn, you can deal an extra 1d6 damage to one Favoured Enemy you hit with a melee weapon or ranged weapon attack, if you do not have disadvantage on the attack roll. Damage increases +1d6 per 4 Ranger levels.
Ranger Level Favoured Foe Damage
2 +1d6
6 +2d6
10 +3d6
14 +4d6
18 +5d6
So it's basically a half-strength sneak attack, which I think fits with the Ranger's placement between Fighter and Rogue in design.
BTW I let Beastmaster Rangers order their beasts as a bonus action, so this is useable by them.