hands_behind_head = both hands or both arms are posed behind the character's own head

hands_behind_back = both hands or both arms are behind the character's own back

wrists_together = a character's own wrists are held/bound close together

arms_together = a character's own arms are held/bound pressing close together

legs_together = a character's own legs are held/bound pressing close together

frogtied = when a leg is bent so much that the calf and the thigh on the same leg are touching, and it is then bound to keep it that way. Often done to both legs, looking like how frogs sit.

wrists_to_ankles = when their wrists are tied next to their ankles

spread_eagle = when a character has all arms and legs spread out (can be with or without bondage, and it can be standing or laying down). The result is a little bit like an X shape, though not always a perfect one.