Rule #0, DM rulings overrule all others, even official source books. You can challenge a ruling if you have a good argument however the DM/GM has final say. Rule-of-Cool is a thing but only sparingly.
Don’t be a Dick. This should go without saying but don’t create unnecessary conflict with the group. Don't be a bully, don’t be racist, sexist, xenophobic etc. Don't bring any real-world grievances, slurs or discrimination into the game.
Be on time. Or give sufficient warning if you are going to be late/absent, preferably at least a day’s warning.
No cheating/fudging. This is my job not yours.
Don’t roll without being asked to (or asking to) first. Your roll may not be counted. You may roll to help yourself make character decisions, like which door to open, but don't do things like checking for traps or making insight checks without asking first.
Boundaries and triggers. I will attempt to keep the games mostly light-hearted avoiding intense topics like rape, suicide and abusive relationships. If something in the game makes you uncomfortable, or could, please let me know. I will then attempt to maneuver away from those topics. You don't need to give me details or tell other players if you don't want to. Likewise, if I, or any other players, tells you to stop regarding certain actions, jokes or topics, then stop. Related: Hard and Soft Limits in Tasha's Guide to Everything.
Skills with Different Abilities (PHB). If you want to use an alternative ability for a skill check, you can make an argument for using that ability, it is up to the DM to allow or deny this. For example, using Strength instead of Charisma for Intimidation if you are crushing someone’s throat.
Ammo tracking. Every time you use a weapon with the ammunition trait, it consumes the relevant ammunition type (unless a magic effect or spell says otherwise). If you can feasibly spend 1 minute searching a battlefield, you can recover half the spent ammo (rounded down) after combat, minus any that are in unreachable places.
Milestone Leveling (DMG). Level ups are also only done during long rests, downtime or time skips.
Simple Encumbrance. 7.5*STR lb. for Tiny, 15*STR lb. for Small/Medium, 30*STR lb. for Large/Powerful Build.
Flanking (DMG). 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.
Disarm (DMG). 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.
Downtime Activities (XGE). Downtime can be handled as described in XGE.
Cleaving Through Creatures (DMG). If the damage of a melee weapon attack is greater than a creature’s remaining hit points, the additional damage can be carried over to another creature within reach, assuming the attack roll would still hit the next creature.
Falling into water (TCE). A creature that falls into water or a similar liquid can use its reaction to make a DC 15 Strength (Athletics) or Dexterity (Acrobatics) check to hit the surface head or feet first. On a successful check, any damage resulting from the fall is halved.
Falling onto a Creature (TCE). If a creature falls into the space of a second creature and neither of them is Tiny, the second creature must succeed on a DC 15 Dexterity saving throw or be impacted by the falling creature, and any damage resulting from the fall is divided evenly between them. The impacted creature is also knocked prone, unless it is two or more sizes larger than the falling creature.
1D&D Exhaustion Rules. Exhaustion is measured on a scale of 0-10, with 10 being death. For levels 1-9, you simply subtract your exhaustion levels from all attack rolls, ability checks and saving throws (unless stated otherwise).
Critical Damage = Roll+Max. For the damage of a critical attack, you roll damage as normal and add the max of the damage die (e.g. a 1d6 weapon will do 1d6+6+mods).
Creating Spells and Items. If you have a cool idea for a new spell or item that your character could invent, discuss it with me and I may allow it.
Evolving Cantrips. Utility Cantrips get stronger at higher levels just like damage cantrips do.
Potions of Unknown Effect. Homebrew potions made from otherwise useless loot taken from monsters.
Pocket Sand. Small chance to blind someone for a short time if you have access to sand or grit (it's pretty weak, it's more of a last resort).
Wheelchair. I liked the concept of the Combat Wheelchair just not the execution, balance and the docs themselves. I decide to make my own simplified version without unnecessary bloat. However, this does not mean the Combat wheelchair is entirely off the table if you want a more in depth and complex version, and/or to use the subclasses.
Official sources and my homebrew are preferred. However UA and other homebrew sources may be allowed if you run it by me first. You can even suggest your own homebrew. See Homebrew.
Ability Scores can be rolled, use Standard Array or Point Buy. Rolling is 4d6 drop lowest for each score (In foundry or discord). You can roll out-of-order. You can also willingly lower any score you wish, to a minimum of 3, but you will not get any extra points for doing this.
Hit Points. Take average or roll on level up, I will allow re-rolling 1s (if you roll two 1s though, tough).
Feats in place of ASI are allowed. Be sure to check out Homebrew for some of my feats.
Customizing Your Origin (TCE). Tasha's Cauldron of Everything has some rules for altering your racial ASIs, proficiencies and languages. You may also make your own suggestions for modifications.
Custom Lineage (TCE). I'll allow the custom lineage race from TCE. Consult me with your ideas and we'll work on your character.
Changing Your Subclass (TCE). If you want to change subclass mid-game, I may allow it if it makes sense for the character to do so (such as changing your cleric’s god). TCE has some guides for this. I may also allow changing feats, fighting styles, warlock pacts, barbarian totems and similar features. This should not be taken lightly and will only be allowed sparingly.
Optional Class Features (TCE). I’ll be allowing the extra features granted by Optional Class Features from TCE.
Backgrounds with Feat (SCC, AAG etc.). Some backgrounds, such as those in Strixhaven or Spelljammer, will grant feats. These feats are only allowed if all the other players get an extra starting feat as well, either by taking the same BGs or getting a free Lv1 feat. However, the backgrounds themselves and other features like expanded spell lists are fine regardless.
WOTC Lore does not matter. By all means, use the given lore and common fantasy tropes to template/influence your characters but do not feel constrained by them. For example, Warforged might be created for a purpose other than war, Kobolds aren't exclusively worshipers of evil dragons, Orcs might be more than just monstrous followers of Gruumsh and so on.
No Unlimited Fly Speeds. Races with fly speeds are not outright banned but you should talk to me first. I am hesitant to allow unlimited fly speeds, however, some comprises may be possible. Things like Aasimar are fine but Aarakocra need some prior discussion.
Secret Bad Guys. If you want to play a character secretly working against the party, or with ulterior motives, we can maybe work something out privately. Understand that you will be expected to mostly work with the party until revealed (e.g. avoid blatantly sabotaging the party frequently) and you should expect to "lose" (e.g. be killed or forced to flee) if the party turns on you after the reveal (i.e. I'm probably not going to let one player just TPK the others out of the blue), you'll then make a new PC (its possible you could still run them in the background if they survived). You can have a change of heart and switch to genuinely working with the party later down the line.
Alternative Spells. If a particular spell would fit your character well but is not on your spell lists, you can make an argument to add it to your spell list or replace a subclass spell with it. For example, a sailor style Storm Sorcerer getting access to my Spectral Crew spell.
Alternative Abilities for features and spells. If you would like to build a character who is different to typical class archetypes by altering which abilities are used for spellcasting, class features, and saving throw proficiencies, I may allow it so long as it makes a certain amount of sense and doesn't make things too unbalanced (i.e. this is not meant to allow you to make OP multiclass builds but may let you make atypical builds to match your RP intentions). A few examples could be; INT for Warlocks or well-read Rangers, WIS for religious Paladins or CHA for gladiator style Fighters.
Polearm Master + Sentinel. No! Fuck you! I’m never allowing that combo again. Either one is fine on its own though.
Wild Magic. Wild magic subclasses are allowed. When you take a subclass you may choose to use the d10000 table instead of the one granted by the subclass. It has less mechanical impact (as it's designed to be system agnostic) but has some really crazy effects that may fun to react to. As DM, I do have veto powers if something is too crazy but I don't intend to use it except in very extreme cases.
Hindering Traits. Mechanical character flaws, not mandatory but allowed. I'll decide on rewards for taking them, if any, on a campaign-by-campaign basis. FYI: I may remove/rebuild this rule in favor of a slightly different system
See respective setting pages.