I've Got More!

This feat captures the essence of a character's most dramatic moments, where characters overcome overwhelming odds through sheer determination. When a character has used up all their expendable resources like spell slots, Ki, Bardic Inspiration, Rage, Second Wind, etc., they can attempt to harness a hidden reserve of energy to reuse one of these skills. When the odds are against them, and their powers are spent, heroes channeling their indomitable spirit can find a wellspring of energy within themselves. The "I've Got More!" feat is a manifestation of this incredible willpower, enabling characters to push beyond their normal limits in times of dire need.

(Creator note: Additionally, consider running this feat as a secret boon for your players to stumble into, an inherent skill your players have know idea they have, until they've earned access in the DM's eyes.

Mechanics:

1. Activation Condition: The feat is available when all of a character's expendable resources (spell slots, Ki, Bardic Inspiration, Rage, Second Wind, etc.) are depleted.

2. Determination Roll: Activate this feat by rolling a d20 and adding your proficiency bonus. The total is compared to the feat's Dynamic Difficulty Class (DC).

3. Dynamic DC:

   • Full Health: DC 20
   • Below 75% Health: DC 18
   • Below 50% Health: DC 16
   • Below 25% Health: DC 14

4. Spell Slot Usage: When used for casting a spell, increase the DC by 1 for each spell level above first.

5. Increasing Difficulty: Each successful activation increases the DC by 5 for subsequent attempts.

6. Action Economy: Regardless of the outcome, attempting to use this feat consumes the same amount of time as the action being attempted (e.g., an Action for a spell that requires an Action to cast). This space in the action economy is spent whether the attempt is successful or not.

7. Exhaustion Risk: Failing the roll by 10 or more results in one level of exhaustion due to the strain.

8. Usage Limitation: This feat can be activated once per long rest. However, once activated, it can be used as often as desired within the same instance of combat.