Va

Short form of "Voice Actor". Often used to refer to the voice actors behind characters in animation works such as anime.

"Wow, she has quite the vibe. Who is her va?"
"It's Sora Amamiya."

GTKBC

Abbreviation/short for 'Going to kill brain cells'.

Used when someone is about to watch/do something particularly brain-damaging due to its sheer stupidity.

Example for usage:
"I'm done chatting for today." - A
"Yeah, same." -B
"GTKBC, cya." -A
"Alright. Will probably do the same. Cya." -B

Izzatso

Lazy version of 'is that so".

Pers A: Hey man, I unlocked a rare character today.
Pers B: Izzatso?