IMY is an abbreviation for “I miss you.”

TTFN is an abbreviation for “ta ta for now.”

TTYL is a texting abbreviation for “talk to you later.”

BRB is a texting abbreviation for “be right back.”

ATM is a texting abbreviation for “at the moment.”

AFAIK is a texting abbreviation for “as far as I know.”

AF is an abbreviation for “as f**k.”  AF is usually placed after a word for emphasis.