Here's a list of such microwords. I will update this when I have time; feel free to write me with more.
- btw - "By the way"
- fwiw - "For what it's worth"
- gg - "Good game!"
- gga - "Good game, all!"
- gge - "Good game, everyone!"
- gj - "Good job!"
- gla - "Good luck, all!"
- gtg - "Got to go"
- lol - "Laugh out loud"
- np - "no problem"
- nh - "nice hand"
- opp - "opponent"
- p - partner, e.g. "gjp" means "Good job, partner!"
- rotfl - "Roll on the floor laughing"
- thx or tx or tks - "Thanks"
- ty - "Thank you"
- tyvm - "Thank you very much"
- vnh - "Very nice hand!"
- wd - "Well done"
- wtg - "Way to go!"
- yw - "You're welcome"
- yvw - "You're very welcome!"
Game-specific abbreviations:
Spades
- gc - "Great cover!" (this sometimes also means "good cards")
- icu or cu - "I see you" (meaning you see that your partner is going nil - often considered table talk, but it depends on how strict you're being)
- nn - "Nice nil!"
- nnu2 - "Nice nil, you two!"
- ns - "Nice set!"
- xcp - "Excellent cover, partner!" (said to someone covering nil)
- gc - "Good cards!" or "good call"
- ne - "Nice euchre!"
- nep - "Nice euchre, p!"