What are the different acronyms people using when they are flying?
Example: GUMPS - Prior to landing - Gas, Undercarriage, Mixture, Props, Switches

For work, and most aircraft I fly:
Left to right sweep.

For Safety:
Skin, Tin, Ticket (Do what ever it takes to save your ass first, then the airplane, then your license)

For Soaring Association Canada:
CISTRSCO - Pre Take Off
C - Controls
I - Instruments
S - Straps
T - Trim/Ballast
R - Release
S - Spoilers/Flaps
C - Canopy
O - Options

CALL - Pre Spin/Stall etc
C - Cockpit
A - Altitude
L - Location
L - Lookout

SWAFTS - Pre Landing
S - Straps
W - WHeel and Water
A - Airspedd
F - Flaps
T - Traffic
S - Spoilers

For the Air Cadet Gliding World:
BCISTRSC - Pre-Takeoff
B - Ballast
C - Controls
I - Instruments
S - Spoilers
T - Trim
R - Release
S - Straps
C - Canopy

SWARTSC - Pre-Landing
S - Spoilers
W - Wind
A - Airspeed
R - Radio
T - Trim/Traffic
S - Straps
C - Canopy

AAAT - Pre-Release
A - Area
A - Altitude
A - Attitude
T - Traffic

ASCOT - Pre Spin/Stall etc
A - Altitude
S - Straps
C - Canopy
O - Objects (loose objects)
T - Terrain / Traffic


....That enough typing for now

PreTake-off:

TILT
Transponder, Ice, Lights, Time

Pre-Takeoff:

BLAM
Boost pump, Lights, transponder to ALT, Mixture Rich

EFOTO-TSB
Engine Failure On Take OFf - Throttle idle, Stick back, Brakes full

EFATO-SLAM
Engine Failure After Take Off - Stick forward, wings Level, Airspeed, Mayday

Isn't there a whole forum already dedicated to this?

There are whole books dedicated to this. People won't search for them at their bookstore, why would they use the search function here?