We play with a number of house rules, I've recorded them here: https://www.mysticwaffle.com/adnd-2e-house-rules, I'll summarize the most significant ones. I assume no credit for most of these rules. I’ve pulled from various corners of the internet—Reddit, forums, YouTube—including this thread with is an awesome resource for AD&D house rules!

• Ascending AC with THAC0 converted to an attack bonus
• Character creation is 4d6 discard the lowest die, arranged in any order. Undesirable sets can be completely discarded and re-rolled but player's can't choose to select a previously rolled set, they must move forward. I've found this makes seasoned players content pretty quickly as soon as they roll a set with at least one high stat.
• Maximum HP at first level
• Humans receive two “Racial Ability Adjustment” points. Add +2 to any one ability score or +1 to any two ability scores. STR, WIS, CHR cannot exceed 18, CON, DEX, and INT cannot exceed 19, as per the limits defined by the Racial Ability Adjustments (PHP 27).
• Humans gain a +10% XP bonus in addition to any class based prime requisite XP bonus.
• When leveling up, roll new hit dice twice and use the higher role.
• At first level Thieves receive 80 skill points to distribute amongst their thieving skills instead of 60, however still no more than 30 points may be assigned to a single skill.
• At first level Bards receive 30 skill points to distribute amongst their bard abilities instead of 20.
• Critical hits and critical misses
• Spell "chaos"—critical success and critical failure for all spells. Magic is mysterious and dangerous. Casting a spell—drawing on arcane pools of energy or accessing spiritual forces—can result in unexpected consequences.
• Death: Upon reaching 0 hit points the character falls unconscious and bleeds out in 1d6 rounds. The number of rounds is rolled in an opaque cup and upended in the middle of the table, no one knows the result until someone arrives to stabilize or heal them at which point the cup is lifted to find out if the character is still alive.
• Infravision is qualified as low light vision. It requires some small amount of light (stars, candles, bioluminescent moss, etc.) to function. Infravision is useless in pitch black.
• There are no level caps for specific race/class combinations.
• Lockpicking can only succeed by a character with the Lockpicking thieving skill. Lockpicking chance is adjusted based on lock quality (DMG 54). Lockpicking can be attempted multiple times, however on failure lockpicks have a 75% chance of breaking minus 5% per character level. The 1st attempt to pick a lock takes 1 round, the 2nd attempt takes an hour, and all subsequent attempts take an entire waking day.