House rules: Most of these are shamelessly stolen from Matt Mercer, with a few tweaks.

Skill Check Criticals: If you roll a Nat20 on a skill check it automatically succeeds, no matter how impossible the task. 

Potions: Players can consume potions as a bonus action if they have them on their person. (ie, if its in a Bag of Holding it takes an action or DM's discretion).

Crits: Nat20 damage is calculated thusly, double the damage on your dice for a critical hit. (So, 2d6+3 becomes 2d6x2+3.)

Resurrection: Players have the option to bring their fallen comrades to a holy place (temple, church, shrine, etc) to attempt to bring them back to life. This involves 3 skill checks and payments of some sort from the players. The starting DC to bring their soul back is generally 10, but if they have been dead for an extended period of time then increase it accordingly. Payments can be coin, gems, things of personal value, and even an exchange of life. The skills can be anything based on the method of payment, but Religion and Medicine are the most common. Players do NOT add anything to their dice roll. If they roll above 10, the DC decreases by 2. If they roll below 10, the DC increases by 3. Once the players have made their checks, the DM makes one final roll that has to beat the new DC in order for resurrection to occur. The DM does NOT add anything to the roll. (So say you started with a DC 10. 1 player failed and 2 succeeded. The new DC would be 9. The DM has to beat that DC by dice roll, or the deceased is forever lost).

Crafting: Crafting magical items, potions, etc only takes 1/6 of the time indicated in the PHB.

Inspiraton: If your players do something really cool or they RP really well, you can grant them a 1d4 to add to any dice roll. This encourages party members to be engaged and think outside the box.

Initimidating Presence (Barbarian Only): Based on STR instead of CHA

Wall of Stone (Spell): Instantaneous and permanent instead of concentration with a duration. 

Movement (Grid Only): Each square represents 5ft.