These are additional rules added to patch over situations in DnD that are coming up often enough to justify rule patches.
Disarms, Rearmed: When you've disarmed someone, you can use a free action to pick up the weapon, as is already RAW legal, or you can punt it ten feet away. That should at least force an enemy to have to suck an attack of opportunity to go get it back.
Grapples, Revised: Grappling can be over a specific area - a limb, the body, or the head, a la Unisystem. The head doesn't do anything special, but you gotta if you want to strangle some little %^&*. A limb puts you at disadvantage to use that limb, and the body gives you a minus d4 to everything. So yes, someone can try to punch or elbow you with the arm you're holding them by, but it'll be less accurate, and a full-body grab will make it tougher but not quite as bad as a limb grab on that limb. The 'zero move' thing still applies, so once you're holding someone they aren't going to take a walk. (Unless they're two sizes bigger, then they hardly give two shits what you're doing.)
When Pushing Attack Comes to Shove: Someone using a Pushing Attack may, as a side benefit, use a Shove attack for free to attempt to knock a target prone. (You make a Strength (Athletics) check contested by the target’s Strength (Athletics) or Dexterity (Acrobatics) check (the target chooses the ability to use). You succeed automatically if the target is incapacitated. If you win the contest, you knock the target prone.)
Yeet To The Street: Once grappled, you can throw a creature with a contest of Athletics vs Athletics/Acrobatics. A character the same size as another character can throw a character 5 feet. For every size larger that a character is, increase the distance by 5 feet; for every size smaller, decrease the distance by 5 feet. Then add 5 feet per Strength +1. This inflicts damage equal to the Strength modifier, or equal to falling damage if falling damage is greater (being thrown off a cliff, for example). If the creature comes to a stop because it hits a wall, person, or other object, both entities take 1d6 damage plus 1d6 damage per size smaller the throwee is than the thrower (or fall damage, if greater).
Fastball Special: Throwing a creature at another creature to attack them works as a Yeet attack; the thrown creature takes damage equal to the strength modifier, and if the attack hits, the attacker inflicts extra damage equal to the sudden-stop damage.
Don't Tase Me: Shocking Grasp can inflict damage to people grappling or being grappled by the target (1 point if the target isn't wearing mostly metal armor, half damage if the target is wearing mostly metal armor). The no-reactions effect means that someone can break a grapple caused by the target of the Shocking Grasp automatically on their turn.
Non-Lethal Damage:
Non-lethal damage is accumulated separately from lethal damage. In order to inflict non-lethal damage, you generally attempt to knock them out or cripple them rather than inflicting fatal wounds; this is often done by striking with the flat of the blade or pommel of the weapon rather than the sharp end. Combatants can choose when to inflict nonlethal damage when damage is dealt. If one wants more realism, 'sharp' attacks such as blades and ranged projectiles can only inflict half nonlethal damage (rounded up); the rest (rounded down) is lethal damage. Energy weapons and attacks (such as a fire bolt) always inflict lethal damage, though they can still be used to weaken a foe so that nonlethal damage can knock them out.
Non-lethal and lethal damage are combined to determine when a subject reaches zero HP; if the subject reaches zero HP due to the lethal damage only, then they are dying with all of the effects thereof. If they are reduced to zero HP in part by nonlethal damage, then they fall unconscious and are stable at zero HP.
* Nonlethal damage is healed at twice the rate of lethal damage during a short rest. Alternately, a person at zero HP recovers 1 HP lost from nonlethal damage after 1d6 x 10 minutes.
Hacking:
Hacking Tools give rudimentary access to a complex computer system, acting sort of like thieves' tools. While accessing a system, a user's Avatar has HP and AC, allowing it to be targeted by attacks by the end system (traps, hostile programs, etc). HP is equal to Wisdom; Technology skill is used as Perception/Investigation for finding things. AC equals 10 + Int modifier. When HP is depleted by traps or obstacles, subject is disconnected.
Hacking Rig gives Virtual Reality access to a system. Int is Dex, Cha is Str, Wis is Con. HP is equal to (Level x (6 + Wisdom Modifier)), TempHP depends on System rating. AC equals 10 + Int mod + Processor rating. 1/2 of damage inflicted to Avatar (nonTempHP) is also inflicted to user as non-lethal damage. As above, when HP is depleted by traps or obstacles, subject is disconnected.
Expanded uses of inspiration:
The Reroll. Use Inspiration to reroll your or someone else's attack, check, or saving throw.
The Crit. Use Inspiration to turn any attack that hits into a critical (it doesn't count as a natural 20, but you get the damage boost as if it is.)
The Spell Slot. Inspiration allows a spellcaster to upcast one of their spells to the next highest slot for free. The spellcaster does not need to actually be able to cast spells at said level to do this.
Get Inspired. Get a flash of Inspiration; the DM reveals a clue, a hidden door, an enemy's weakness, or something else they may have missed.
Suggestion. Make a suggestion about the current scene, subject to DM veto. (For example, 'could the rocks above the bandits be loose'?) If the DM vetos the suggestion, the Inspiration is not spent.
Karma. You can beg for a use of Inspiration when you're out of Inspiration. However, the DM gets a point of Karma, which lets them use Inspiration when they see fit for one of the baddies.
Paragon Monsters:
Paragon monsters are more complicated than regular monsters, and have some or all of the following traits:
Paragon Fortitude. The creature has multiple pools of hit points, each of which is tracked separately. All damage and healing must be completely applied to only one pool. When a pool is reduced to zero, all ongoing conditions and effects affecting the creature end. Once a pool is reduced to zero, that pool cannot receive any healing until after a long rest. If all hit of the point pools are reduced to zero, the creature is killed.
Paragon Exhaustion. The creature may take one complete turn in each round of combat for each hit point pool it has above zero and receives one reaction between each of its turns. When a pool of hit points has been reduced to zero, the creature loses one turn each round thereafter. The creature determines initiative normally for its first turn, though it gains advantage on the roll. Each subsequent turn is inserted immediately after any one PC’s turn in the initiative order.
Paragon Fury. The creature may take one additional turn in each round of combat for each of its hit point pools that have been reduced to zero. The creature determines initiative normally for its first turn, though it gains advantage on the roll. Each subsequent turn the creature gains is inserted immediately after any one PC’s turn in the initiative order.
Paragon Transformation. The creature has multiple forms, each corresponding to one of the creature's hit point pools. The creature begins the battle in its first form. Once that form's hit point pool has been reduced to zero, it assumes its next form immediately. Statistics, traits, or actions keyed to a specific form are only used when the creature is in that form.
Take 10, Take 20:
If there's no time pressure, you can take 10 on an ability check by taking twice as long to get it done.
If something is repeatable and the only factor is time (there is no meaningful consequence of failure), you can take 10 times as long as normal and automatically get the best possible outcome (effectively taking 20 on the check.)
Five Foot Step: You can take a five foot step (as your move action) without provoking an attack of opportunity.
Potion Drinking: Potions with a quantifiable impact (read: healing potions) can be chugged as a bonus action (roll healing randomly), or drunk carefully as a standard action (maximum healing). They can also give potions to an ally as a standard action (roll healing randomly). Other potions require an action (to carefully measure the dose, in the case of multi-dose potions, or to drain every drop of the potion.)