Because the Two Weapon combat feat, Two-Handed Weapon feat and Shield feats were so good, and very reminiscent of their second edition weapon styles, I was surprised there was no one handed finesse build. There is Defensive Duelist, but it’s not actually all that good. Here I present an alternate feat for Dungeon Masters to consider.
While utilizing a one-handed finesse weapon in melee with nothing in your other hand, you gain +1 to AC and the following benefits:
You can take -5 to attack to gain Reach if your weapon does not already have it.
Whenever you score a critical hit, your next attack on that foe has advantage. If you fail to attack that foe before the end of your next turn you lose this advantage.