I am commonly found code golfing in:

• brainfuck
• Befunge-93
• ><>

• Hexagony
• Befunge-98
• Brain-Flak
• Lost

Planning to learn:

Posts I'm proud of (in descending order):

• Hexagony Quine (Hexagony, 383 bytes)
• Halting Problem Paradox (brainfuck, 4376 bytes)
• Mutually Exclusive Quines (><>, 42+42=82 bytes)
• Programming in a Pristine World (><>, 17 bytes)
• Lost Quine (Lost, 70 bytes)
• "Hello, World!" in Hexagony (Hexagony, 29 bytes)
• FizzBuzz (brainfuck, 350 277 bytes)
• Find the missing number to make the input divisible by 9 (Befunge-93, 16 bytes)

If someone comments on a question "I wish there was a brainfuck solution", I am obliged to provide one.

I also know a variety of actually functional languages such as Python and PHP, but don't know the tricks to golf them.