A few different motor mounting screw selections for ya.  come in a pack of 3 You get 3 screws total in case you lose one.

Regular Motor Screws - Use a 1.5mm hex driver to install, Used to mount the motor to the motor plate. Have a round head like stock scx24 motor screws - M2x3mm

High Clearance Motor Screws - Have a Phillips head Flat face to mount motors to the motor plate that need more clearance than the round head screws.  The screws are M2x3mm 

Brushless mount Motor Screws - Use a 1.5mm hex driver to install. Used in most cases to mount a brushless motor to the brushless forward facing mounts. M2x10mm