Can get sneak attack with Great Sword (hopefully a bug)
Food heals health (hopefully a bug)
Scrolls can be used by anyone (hopefully a bug)
Grease is flammable (From Sage Advice, JC states it is not)
What about stuff that a bit grey? Attacking from above in BG3 gives advantage, that not really in the rules but could be a DM call / interpretation so definitely a house rule in BG3.