How does one spread attack damage across low hit point creatures with a level 3 fighter?

Question

We are looking at an encounter where a dozen or more 2 hit point creatures may be attacking a party of max level 3.

Assuming as a DM we decide against using the “Cleaving through Creatures” optional rule (DMG p.272) - what other ways might a Level 3 fighter maximize their attacks or area of effect (AoE) damage?

We are wondering if dual wielding daggers, throwing knives, or some other approach to using weapons or skills might be effective for spreading damage. For example, it seems as if burning oil could be effective in this situation (depending upon the spread of the opponents.) Though not technically damage, sleep spells might also be effective. 3rd level Moon Druids might turn into a Giant Hyena to get Rampage giving them an additional attack if they kill one creature in a round. Mage’s Burning Hands gives AoE. These are some examples, but perhaps there are other options that are even better for this particular class?

What are the maximum number of attacks or AoE damage that a fighter could achieve at level 3? In other words, what are the ways in which this low level class can spread their damage to be “thin and wide”?

(Note: we have edited this to be class specific as the original was tagged as too broad. Variation questions for other classes have been added.)

Answer 1

I'm making a number of assumptions about the situation that may or may not be warranted -- like, you don't have magic items, you can't prepare traps, the enemies will be bunched up, etc -- so forgive me if this doesn't work. However, within those assumptions, there are a few clear front-runners.

1. The Sword Burst cantrip (available to Elven fighters or Eldritch Knights) allows 1d6 damage against every creature within 5 ft that fails its Dexterity save, potentially every round.
2. The Battle Master maneuver Sweeping Attack, while certainly underwhelming, doesn't limit the number of times it can chain (although you are limited to superiority dice, which are 4 without a feat). With two-weapon fighting and additional superiority dice from a feat, you could dispatch up to eight weak creatures in one turn with this (you'd then be out of superiority dice).
3. However, the Arcane Archer would allow you to dispatch up to 50 tightly-packed creatures over two rounds with the Bursting Arrow option (and then you'd be out of arcane arrow charges).
4. The Fighting Style Tunnel Fighter from Light, Dark, Underdark allows you to make an unlimited number of opportunity attacks in a turn, which combines well with the feat Polearm Master (allowing you to make opportunity attacks when creatures enter the reach of your weapon). This could potentially dispatch an unlimited number of creatures, assuming they all moved towards you.

Answer 2

A Fighter 3 with a Martial Archetype of Battle Master could have up to seven attacks in one round using Maneuvers:

1. Normal attack using a Light Weapon as an Attack Action.
2. Sweeping Attack Maneuver on successful hit using one superiority die.
3. Offhand attack using a Light Weapon as a Bonus Action (potentially with ability modifier from Two-Weapon Fighting Style).
4. Sweeping Attack Maneuver on successful hit using one superiority die.
5. Action Surge for third attack as an additional Attack Action.
6. Sweeping Attack Maneuver on successful hit using one superiority die.
7. Riposte Maneuver using one superiority die and Reaction.

Sweeping Attack Maneuver: When you hit a creature with a melee weapon attack, you can expend one superiority die to attempt to damage another creature with the same attack. Choose another creature within 5 feet of the original target and within your reach. If the original attack roll would hit the second creature, it takes damage equal to the number you roll on your superiority die. The damage is of the same type dealt by the original attack.

Riposte: When a creature misses you with a melee attack, you can use your reaction and expend one superiority die to make a melee attack against the creature. If you hit, you add the superiority die to the attack's damage roll.

This presumes the Fighter is somehow surrounded by the creatures or is holding a doorway or similar chokepoint with the creatures crowding around. This round essentially exhausts all of the Fighter's ability options until a Short Rest is taken. Alternatively, an Eldritch Knight Archetype could use AoE spells like Burning Hands as well.