Most popular types of sandals:

Huarache –  A Mexican sandal of woven leather thongs forming vamp.

Flip-flops or Zori – originally a Japanese sandal with sponge rubber sole held on the foot by two straps which come up between the first and second toes and fasten to the side of the sole.

Gladiator – flat with several wide cross straps to hold the sole to the foot and one wide strap around the ankle. Copied from sandals worn in roman arenas by gladiators.