This part is just to add hax his page is missing:
Soul Manipulation and Gravity Manipulation: Blue Mode has Sans turn his opponent blue and he gives gravity to their SOUL, pretty blatant
Dimensional Storage: In the monster physiology key as optional equipment;
Invulnerability Negation: Sans is the only monster capable of negating the invulnerability stat in his fight, always doing one damage per frame
Instinctive Reactions: Can dodge even when he is asleep
Afterimage Creation: Is show to be in multiple places at once at the end of his fight.
Spatial Manipulation: Can completely manipulate the battle box, like extending it to make Chara fall way more than they actually should
Resistance to Soul Manipulation and Radiation Manipulation: In the monster physiology key; All monster bodies are directly attuned to their souls, therefore any damage done to their body affects the soul; Monsters drink radioactive waste as energy drinks