Leg-up full turn
Full turn with leg at horizontal
The letter L
The single L turn is quite uncommon on floor for the same reason as the double turn, it’s just not worth enough to bother doing it or risk the deductions. Most gymnasts who aren’t attempting D turns will simply ignore the concept of turns altogether.
The single L turn is the domain of those very low level routines that desperately need a B element to count, those who seriously miscalculated and under-rotated their intended double L turns, or those who feel comfortable enough with it to perform it in combination with a more difficult turn for bonus.