In Tabletop Games I is for…
Improvement Points (IP)
Some RPGs ditch the traditional experience points in favour of Improvement Points. Instead of levelling up in one big jump, you gradually spend IP to improve skills or stats. Games like Call of Cthulhu use this method, rewarding players for actually using skills in-game rather than just collecting XP like a hoarder.
Input Randomness
Some board games love to keep players on their toes by throwing in a bit of randomness. Input randomness happens before you make a decision—think of rolling dice to determine resources in Catan or revealing new event cards in Pandemic. It sets the stage, shaping your strategy without completely derailing your control. This type of randomness can add excitement and variety while still letting skill play a major role.
Have I missed anything?