I notice I haven't been into touch too much with all the abbreviations lately so I had to learn a lot XD, really cool post idea.
Gotta be careful tho, Aa could stand for both "Arcane Ability" but also has been used to refer to "Arcane Artifact".

Also some more abbreviations I hear a lot:
Irl --> In Real Life
Tc --> Take Care
Gl --> Both Good Luck and Gold Loot
Ms --> Movement Speed
Cya --> See you later
Ed --> Elite damage
Bd --> Boss damage

Maybe these are useful for fake or real boomers like me lmao