For my games, I've designed a draconic humanoid race - not Kobold Press' dragonkin, nor a conversion of 5e's dragonborn, but something of my own. When creating an NPC with this race, I considered giving him this trait, with the intention of also making available for any character of that race.
Dragon's Talons (Draconian)
Your hands are shaped more like the claws of your dragon ancestors, and are just as deadly.
Benefit: You gain two claw attacks, which are primary attacks that deal 1d4 points of damage. However, you take a -4 penalty to attack and damage rolls with manufactured weapons that you wield with either or both of your hands.
I realize that getting natural attacks at such a low cost might enable some cheesiness, especially for monks, but I'm uncertain how I could balance it, or if it's even such a significant issue. What do you think?