House rules I'm rather fond of;
*Multi-classing does not blend your spell slots together. Each class has it's own pool of slots.
*Skill checks - it's easy, roll =/under your relevant ability score. Having advantage etc allows you to roll multiple dice & take the best. These sources stack. This is in place more & more because I"M LAZY & don't set DCs. And our newest player seems to understand this easier than adding all the mods.
*PvP? Rolling dice against one another? I'm neither for nor against PvP. I AM against the PCs somehow being immune to things that would normally affect them if any NPC/monster had attempted it.
OK: PC <---> NPC/monster, OK: NPC/monster <--->NPC/monster, but "because" PC=/= PC is not OK??? Nope.
So if/when it comes to PCs rolling dice against each other? That's on them. Normal game rules will apply.
*Stat generation.
Each player gets to decide for themselves wich method to use: 4d6-1 roll method, standard array, or standard PB.
IF YOU ROLL: You will do so in front of the group & you will play the results in good faith. There's no mercy, no re-rolls, etc. Afterall, if you wanted to avoid risking bad stats you had two other methods to choose from. And yet you were perfectly happy to gamble....
*Stat Envy - So you rolled low & everyone else seems "better"? So someone gambled & got lucky, rolling higher than PB/Array would have yielded? Nobody wants to hear about it. You were all given the same options. Those who lost at gambling? Didn't have to gamble, but chose to anyways. Those who played it safe? Might've gotten just as lucky if they'd taken the chance....
*Crits
Roll the damage, add all mods as normal & tally it up. Then double it.
I'm not into wasting time worrying about wich mods do/don't stack & why.
** I tried simply having crits do max damage (after all mods) x2 - but the players insisted on rolling(?) Er, OK.... I mean, they know & don't care that I simply x2 the monster damage on crits against them. Yet they insist on rolling for their PCs. (shrugs)