Diameter
Make sure the prop physically fits the frame size.
What to check
Pitch
Higher pitch can feel more aggressive but may increase current draw.
Blade count
Tri-blade props are common for freestyle, while bi-blade props can be more efficient.
FPV propellers
Choose FPV propellers by size, pitch and blade count
The propeller must fit the frame, match the motor and avoid excessive load on the ESC and battery. Diameter, pitch and blade count all change how the build feels.
Pick propellers