Homebrew systems for D&D 5e

Typing this out while I’m finishing my break for my day-job. Here are some homebrew system that I think your table might be intrigued to try out:

1′ Square = 10 ft

This is a small change for tables who like to use grids and maps in their games. A few other people have discussed this idea, but I’d like to share a few extra rules you can implement.

Do the idea is that instead of the usual 1′ = 5ft rule, grids are now demarcated in 10ft squares; each square is now four times larger than before.

The trick here is to allow creatures to continue occupying their original square sizes. In this scenario, that would mean that four medium creatures would now be able to squeeze into one square. You then tweak the rules-as-written into the following:

1. Creatures become engaged in combat with a target when they enter the same square. Creatures may trigger attacks of opportunity from an attacker when they exit the square without disengaging.
2. One square can hold 8 Tiny creatures, 6 Small creatures, 4 Medium Creatures, 1 Large creature, 1 Huge creature, 1/4 Gargantuan, 1/9 Colossal.
3. Squares can become over-filled: e.g. If a square has one huge creature, and a medium-sized attacker enters the square, the square becomes over-filled. At the end of the round, the smallest-sized creature who last entered the square will be forced out of the square. This may trigger attacks of opportunity. e.g. The medium-sized creature is ejected from the square at the end of the round, and the huge creature can spend a reaction to make an attack of opportunity.
4. When two allies are in the same square and attacking an enemy, they are flanking the enemy and gain +2 to Hit. If three or more allies are in the same square and attacking an enemy, they gain +5 to Hit.
5. To receive the benefits of cover, creatures must occupy the same square as the cover. Cover can have different sizes, and thus only allow different number of creatures to occupy it.

And that’s it! I think this small tweak has interesting effects on gameplay; it’s a simple way to determine flanking and who is in cover. It allows larger ranges, and thus more interesting positions.