Use the correct-size Allen key first and press it in firmly
Tap a slightly larger Torx bit into the stripped socket with a hammer
Apply penetrating oil and let it soak
Use locking pliers if any part of the screw head is exposed
Cut a straight slot in the head with a rotary tool and use a flathead screwdriver
Use a screw extractor kit
Drill a small pilot hole and use a left-hand drill bit
Apply heat to loosen thread locker if present
Strike the driver lightly while turning to break the bond
Add rubber band material for extra grip if the stripping is minor
Weld or epoxy a nut onto the screw head if accessible
Drill out the screw completely if all else fails
Replace the screw after removal