You Have a Reaction. You Just Forgot You Have One.

Reactions are the most powerful resource on a D&D character sheet and the easiest to forget mid-fight. Here's the one habit -- and the tracker -- that keeps opportunity attacks, Shield, and Counterspell from disappearing into the noise of combat.

The rogue slips past your fighter to stab the wizard in the back row. Nobody says a word. The fighter had a reaction available all game, and everyone -- including you -- forgot it existed until the rogue was already gone.

This isn't a one-off. Reactions are the single most under-used resource in D&D combat, and it's not because players don't understand them. It's because reactions live on the wrong clock. Everything else on a character sheet ticks along with "my turn" -- spell slots get spent on my turn, HP changes on my turn, I roll initiative and I act. A reaction breaks that rhythm on purpose: it triggers during someone else's turn, resets at the start of your own, and only works if you notice the trigger in the two seconds before it passes. Nothing about the character sheet reminds anyone to watch for it.

The reactions everyone forgets

Opportunity attacks are the obvious one, but they're not the only casualty. Shield and Absorb Elements need to be declared before damage lands, not after. Counterspell only works in the same breath as the enemy's casting. Uncanny Dodge and Hellish Rebuke both require someone to remember, mid-chaos, that they haven't used their reaction yet this round. Half of these are specifically designed as surprises or counters, which means the only version of "using it well" is using it in a window that's already closing by the time anyone thinks to check.

The fix isn't a rules change. It's making "reaction available" a visible state instead of a fact someone has to recall from memory.

Make it visible, not memorized

The simplest version: at the top of each round, not each individual turn, call out that reactions are live. Have each player flip a token, move a bead, or check a box the instant they use theirs, and reset it visibly at the start of their own next turn, since that's when it actually refreshes, not when the round ends. That one change turns a passive memory problem into something everyone at the table can see without asking.

If you're running combat in Virtual Combat Simulator, this is already sitting on the shared board -- each combatant carries a reaction-used flag that clears automatically at the top of their turn, the same way their HP and conditions do. Nobody has to ask "wait, did you already use yours?" mid-fight, because the answer is already on screen.

The rogue might still get away with the backstab. But it should be because your fighter chose not to swing, not because the table forgot they could.

You Have a Reaction. You Just Forgot You Have One.