neck strengthening?

What are some good exercises to strengthen your neck muscles? I have heard bridging on your head can be effective, and I have seen Muy Thai fighters sitting on a bench, with a towel with a weight in it hanging from their teeth, raising it with their neck. Are these effective exercises? Are there any danger to them?

Any input is appreciated, and I'd also appreciate links/advice on strength routines using dumbbells at home.

I did neck bridges with weights. They worked out well.

Take a 45lb plate and lay it flat on your stomach and than bridge. Add more weight as your neck gets stronger.

I haven't had any injures from bridging. But make sure
your warmed up before using the plates.

dont be that guy that comes into the gym and uses the hamstring curl machine for neck presses, please.

Deadlifts, shrugs, cleans/powercleans or get a neckharness... or alternatively make one yourself.