There's so many options and rules that get forgotten and this makes the divide between martials and casters even bigger.

# Disarm A creature can use a weapon attack to knock a weapon or another item from a target's grasp. The attacker makes an attack roll contested by the target's Strength (Athletics) check or Dexterity (Acrobatics) check. If the attacker wins the contest, the attack causes no damage or other ill effect, but the defender drops the item.

The attacker has disadvantage on its attack roll if the target is holding the item with two or more hands. The target has advantage on its ability check if it is larger than the attacking creature, or disadvantage if it is smaller.

A fighter can disarm a caster from his casting focus, does the caster have a little bag of components to cast spells? Can the rogue then pickpocket tgos as an action as well? You can shut down or severely make life difficult for a caster that way.

Mark

This option makes it easier for melee combatants to harry each other with opportunity attacks.

When a creature makes a melee attack, it can also mark its target. Until the end of the attacker's next turn, any opportunity attack it makes against the marked target has advantage. The opportunity attack doesn't expend the attacker's reaction, but the attacker can't make the attack if anything, such as the incapacitated condition or the shocking grasp spell, is preventing it from taking reactions. The attacker is limited to one opportunity attack per turn.

# Shove Aside With this option, a creature uses the special shove attack from the Player's Handbook to force a target to the side, rather than away. The attacker has disadvantage on its Strength (Athletics) check when it does so. If that check is successful, the attacker moves the target 5 feet to a different space within its reach.

Tumble

A creature can try to tumble through a hostile creature's space, ducking and weaving past the opponent. As an action or a bonus action, the tumbler makes a Dexterity (Acrobatics) check contested by the hostile creature's Dexterity (Acrobatics) check. If the tumbler wins the contest, it can move through the hostile creature's space once this turn.

# Cleaving Through Creatures DMG p272 If your player characters regularly fight hordes of lower-level monsters, consider using this optional rule to help speed up such fights.

When a melee attack reduces an undamaged creature to 0 hit points, any excess damage from that attack might carry over to another creature nearby. The attacker targets another creature within reach and, if the original attack roll can hit it, applies any remaining damage to it. If that creature was undamaged and is likewise reduced to 0 hit points, repeat this process, carrying over the remaining damage until there are no valid targets, or until the damage carried over fails to reduce an undamaged creature to 0 hit points.

Another way to make melee characters strong against minions, here I would rule that something like a divine smite still only applies to one creature.

# Flanking DMG p251 If you regularly use miniatures, flanking gives combatants a simple way to gain advantage on attack rolls against a common enemy.

A creature can't flank an enemy that it can't see. A creature also can't flank while it is incapacitated. A Large or larger creature is flanking as long as at least one square or hex of its space qualifies for flanking.

Flanking on Squares. When a creature and at least one of its allies are adjacent to an enemy and on opposite sides or corners of the enemy's space, they flank that enemy, and each of them has advantage on melee attack rolls against that enemy.

When in doubt about whether two creatures flank an enemy on a grid, trace an imaginary line between the centers of the creatures' spaces. If the line passes through opposite sides or corners of the enemy's space, the enemy is flanked.

Flanking makes melee characters super dangerous with automatic advantage against one enemy. This makes combat position very strong.

In the end there's also encumbrances, you will be surprised how little a character with 8 STR can carry.

There are probably other variant or homebrew rules but these are all on the standars 5e DMG book