What causes toe cramps?

Lots of reasons: Bunions, hammertoes, high arches, flat feet, shoes are some of the reasons. Need more information before a better answer is given. Which toes, any activites when they cramp, type of shoes worn most of the time, foot deformities, overall health. See a podiatrist if it's a real problem.

Depends: Can be from excessive strain on tendons and soft tissue, potassium or magnesium defficiency. Do cramps occur when active on feet or only when at rest?

Few things: Dehydration, overusage of tendons/muscles, vitamin deficincies. (i.E potassium, magnesium.).