there were so many rules that never saw play in my experience. it’s wild to consider
examples include
- Psionics
- Different AC vs different types of damage
- Grappling
- Time required to memorize spells (was like 10 minutes per spell level of study to memorize)
- Training times
- Managing material components for spells
- Encumbrance
- Spellbook costs
- Morale (it’s big in OSR stuff but not so much in tradional AD&D actual play)
- Anything that gives or takes away experience levels on the fly (heroism potions and vampires as written)
- Weapon speeds
- Any vehicular combat rules
- Rules for maneuverability in flight