re

«re» pronounced (r) is a french abbreviation that u can use only by messages.
It means that you’re back in the conversation.

You: «Wait my mom calls me. I’ll be right back»
Friend: «ok»
*2 minutes later*
You: «re»
Friend: «cool !! Ok so I was telling you the she arrived when he....»

ST

ST has a lot of meaning, one of them is the abbreviation of «Stranger Things».
I think I don’t have to explain what it is.
You can use it by messages

You: «I’m so excited for ST’s season 4»
Friend: «me too»