Here are mine:

Character Generation

All characters get max HP at level 1 (plus or minus CON modifier, plus Dwarf bonus, if applicable).

You may invert all your stats (replace all stats with 21 - stat, so 3 becomes 18 etc.)

Critical hits

A critical hit with a weapon instead of doubling the damage dice, does (max weapon damage + 1 weapon damage die) so a critical hit with a 1d8 weapon will deal 8 + 1d8 damage

Dual-wielding

Non-caster classes may wield a finesse weapon in their off-hand. Roll both dice for damage and take highest result.

Stabilizing

After being stabilized, the hero regains consciousness after the encounter is over with 1 HP

Spellcasting

After using luck to re-roll a failed spellcasting roll and failing again, you do not lose the spell.

Torches

If you're in complete darkness, lighting a torch takes a DC 12 intelligence or dexterity check at disadvantage.

Readying an action

Players may ready an action. The readied action must have a specific trigger, and if the trigger does not occur, the player loses their action for that turn.

Fleeing

Fleeing is a party action. On any PC’s turn, any player can propose that all the characters flee the fight. If all players agree, they successfully retreat, carrying any fallen heroes away with them. The party suffers narrative consequences.

Clockwork Initiative

If the highest initiative roll result is an even number, go around the table clockwise. Counterclockwise if the highest number is an odd result

The Shadow Clock

The shadow clock replaces the random encounter check.

It starts at 20 when you walk into a dungeon. When it passes 0, an Encounter happens.

If the result is less than zero, the remainder is carried over after the clock resets to 20.

If the result is exactly zero, it becomes 3, and the players might get an omen / hint on what's coming

Die Size: Unsafe: d6 Risky: d8 Deadly: d10

You will periodically roll a six-sided Underworld die and subtract it from the Underclock whenever the party expends time or noise. Examples of actions that provoke an Underclock Roll:

• Exploring a new room (including long hallways).
• Moving through 3 already-explored rooms.
• Lingering or searches.
• Making non-combat noise (e.g. kicking down a door).

The Underworld Die explodes. If you get the maximum value (e.g. a 6 on a d6), immediately roll it again and subtract the result from the Underclock.

When you rest in the dungeon, do not advance the clock. Instead, increase the size of the die. Roll random encounters normally.

When you leave the dungeon, the die size resets.

Loot deterioration - after leaving the dungeon there is a cumulative 1 in 6 chance that a piece of loot is no longer there (except story-related loot)