Mechanus' Mettle (5e Feat)
From D&D Wiki
Prerequisites: Warforged race
You've been built to surpass all organic life. It's time to act like it.
Gain a +1 in STR, DEX or CON.
Gain proficiency in your choice of Athletics or Acrobatics. If you already have proficiency in your chosen proficiency, double your proficiency bonus for all checks and saves made using it.
Once per long rest, you can choose to have advantage on any charisma saving throw to resist being feared or charmed.