The Homebrew Honeypot

Elden Ring babyyyyyyihaventplayedit

(Disclaimer: I just want to play with my dudes, and they all know 5e, so that's what we're playing.)

So you want to homebrew 5e. There's 2 basic ways to do it:

Ignoring rules is easy; just ignore the rules for item weight, rations, encumbrance, exhaustion, hit dice, ammunition, etc. etc. I ask my players to ignore unconsciousness at 0 HP and it works out fairly well. Even the RAWest of RAW groups do this all the time, and most tables won't bat an eye.

Adding rules is harder; everyone needs to buy in, and then everyone needs to remember the new shit. 5e has quite a few rules already, the mental burden of which is spread thin between players and DMs. Getting folks to remember whole new subsystems at the start of a campaign is daunting.

The approach I'm taking for my new project (a Soulsborne boss rush, get @ me lichesgetstitches) is to sprinkle NPCs and items around the map that add homebrew to the game, piecemeal. Introducing them one at a time, as well as tying them to concrete items and NPCs, will hopefully improve long-term retention for the new subsystems. Essentially, "tricking" my players into playtesting my homebrew.

[note: this doesn't work with "nerfs"; you need to start the campaign with those in mind]

Some ideas:

• The furtive ruin-runner teaches the party to dodgeroll (use your reaction to move up to your base movement speed - 20ft). This doesn't replace AC-based combat, but it adds an additional defense to heavy area of effect attacks. The added versatility comes at the expense of a limited resource.
• Pretty much any NPC can teach a combat technique to the party and introduce another layer to 5e combat. You can use this for shields will be splintered, among other things.
• The scarred veteran teaches the party to lean in (use your reaction when attacked; set your AC to 0 until your turn to attack back immediately). Additionally, if the sum of your attack exceeds theirs, you may parry.
• A surefire way to get a mechanic to stick in a party's mind is to make it a primary tactic of one of the monsters. I want more modules to pull that trick, the "oh, now I get to do the thing!" It's fun.
  
• Drink the immortal water in the empty palace. You don't fall unconscious at 0 HP.
• Alternatively, you can "spend" a death saving throw (doesn't recover until combat ends) to remain at 1 HP and not go to 0.
  

[I hope you see the theme here; pretty much all the combat-related abilities are traps that let me ramp up the lethality of my boss monsters.]

• The Socketer's tools, bestowed by (or stolen from) the grumpy blacksmith. Unlocks socketing and re-socketing of item enchantments, allowing for fun mix-and-matching between boss rush attempts (as well as silly stuff like horned helmets that deal +2d6 fire damage on hit).
• Metamorphose Seeds: Eat one to replace any of your RAW class abilities with a random one. Just let the party take as many as they want. (One weird pill doctors won't tell you about! Smuggling GLOG templates into 5e has never been easier!)

Oh, btw: if you allow long rests all the time (wherever there is a bonfire), you won't have to waste your time modding the short rest system. Yes, the adventuring day is broken and no one knows how to design around it. My philosophy for 5e is this: only 1 combat per rest, so make it a good one.