This post is based on the Wikipedia list of superhuman abilities. If you have a superpower that I consider non-canon, I'll ask you to change it. Any abilities on the above page not mentioned below will most likely be accepted.

Means


ALL superpowers must be due to mutation, either inherited or induced, e.g. from exposure to radiation.
NO powers or abilities may be magical, due to inhuman nature, or derived from objects/artefacts. So no mythical creatures, mages, etc.


Unacceptable Superpowers


Darkness or Shadow Manipulation - Ability to create or manipulate darkness, often by mentally accessing a dimension of dark energy (the Darkforce dimension in Marvel Comics, and the Shadowlands in DC Comics) and manipulating it.

Mediumship - Ability to see and communicate with the dead (i.e., ghosts).

Some forms of Summoning - Ability to summon beings or objects for assistance. Conjuring or summoning objects and living people is fine, summoning spirits or ghosts is not.