Two-weapon fighting rules, per the Player's Handbook (page 195):
When you take the Attack action and attack with a light melee weapon that you're holding in one hand, you can use a bonus action to attack with a different light melee weapon that you're holding in the other hand. You don't add your ability modifier to the damage of the bonus attack, unless that modifier is negative.
Per my earlier question, I am allowed to use different weapons for an Attack action if I have the Extra Attack class feature. Let's assume I did just that, attacking once each with a hand-axe and once with a shortsword. Am I allowed to afterwards perform a Two Weapon Fighting bonus attack with one of these weapons?
Best Answer
Yes
The bonus action has three criteria for triggering:
If you have multiple attacks in a single Attack action because of Extra Attack, you only need to consider one of the individual attacks you make when triggering the two-weapon-fighting bonus action, not the entire Attack action and all attacks you made as part of it.
So if you are fighting with a shortsword and a handaxe, and you make one attack with each as part of your Attack action:
Of course, you still only get one bonus action per turn - so TWF only ever gets you one bonus attack, even if you have a choice of multiple weapons you could use it with.