Ezra’s Large Race Ruling (Revised):
As a large race, you are bigger than others, and this often makes you stronger, but gives you problems when interacting with a society made for Medium-Small creatures.
Regardless of what you choose, weapons created for your size are stronger (polearm weapons such as the pike, spear, and halberd have an additional reach of 5 feet, and weapons made for you deal additional damage.)
1 -> 1d4 -> 1d6 -> 1d8 -> 1d10 -> 1d12 -> 2d10
2d6 -> 3d6
Variant Rule: To replace undersized or oversized weapons, you may just make large races do +2 to damage instead of the above system.
As a large creature, you can push, drag, lift, and carry twice as much as a medium or small creature.
Heavy weapons for smaller races are still too heavy for you to use with one hand. Even with something such as the dual wielder feat.
You cannot use light weapons made for medium races without disadvantage on melee attacks, your hands are too beefy.
For weapons with the thrown property (for large and medium weapons), if you use your strength for the attack roll, it adds an additional 20 feet to both ranges.
For weapons with the versatile for medium creatures property, you deal their higher (parenthesis) damage dice, regardless of if they're being used in one hand or not
Your meaty hands deal 2 damage on an unarmed strike, unless you have a feature that gives you another means of doing this.
You also take up a 10×10 space on a battle map, instead of a 5×5. This enables you to be surrounded easier. (Variant: You may only take up a 15×5 space, all the time, which still enables creatures to attack you from more sides than a medium creature, but allows you to move through spaces easier. This disallows the use of Shimmy [unless your dm allows you to be super wide], which is described later.)
Large races may also have trouble when finding a mount. You definitely couldn't ride horses, so you would have to ask your dungeon master to have something different if you were planning on mounted combat.
Underwater combat is the same for you as it is for other races.
You have a naturally occuring -1 to your AC, and your dexterity stat is capped at 18, you're just not as nimble as others. (Variant: Your armor class when calculated with your dexterity has a further -1 penalty to it, rather than having your stat capped, still having room for skilled, ham sized hands.)
Shimmy: For thin corridors your enormous porkchop body cannot get through, you may ask your DM if you can shimmy through it. When you shimmy, your frontal body is wider, but you take up less space. You would still be 10-15 feet tall, but the space you take up would only be 15 feet long and five feet wide. Your arms are stuck out to the side/behind you, and you're probably sucking in your chest.
Large creatures have more trouble finding cover, anything that provides half cover for medium creatures, provides no cover for large creatures. Three quarters cover for medium creatures is only half cover for large creatures, and total cover, while not ignored by large races, is harder to achieve. If something would normally give a medium or small race total cover, but not completely cover a large creature, they may only have three quarters cover.
You have disadvantage on checks made to take the Hide action where medium creatures would roll normally. You also cannot take the dodge action at all.
Your DM may make it easier for you to clear smaller, less complex obstacles, like 3-6 feet high barricades, small cliffs, and the like. But more complicated roadblocks, like larger cliffs with only natural footholds and things to grab, and possibly fragile terrain may give way to your immense weight. My preference would be increasing or decreasing the DCs of checks made to interact with these environmental aspects by 2 or 3, or have some you cannot travel up at all.
Difficult terrain for medium creatures may not have much of an effect on you, ice would still cause you to slip, but tiny objects in your way, or holes in the floor may not even hinder your pace.
Running water or wind wouldn't have the same effect on you as it does a medium/small race. You would have advantage on moving through such spaces unless they were strong or big enough (deep enough for water.)
Enhanced Equipment Cost:
As your body is much bigger than others, normal amor and equipment costs twice as much as normal, it takes more time, material, and effort.
Battleaxe: 10gp -> 20gp.
Chain Mail: 75gp -> 150gp
Variant: Your class' starting equipment is made for medium creatures, but anything from your background would be made for you.