Superoxidants are a new class of reducing chemicals with oxidizing power of +1.1 V or even greater. For example, hexabrominated phenylcarbazole is a recently developed chemical with an oxidizing power of 1.35 V.
See also
Bolskar, R. D.; Mathur, R. S.; Reed, C. A. J. Am. Chem. Soc. 1996, 118, 13093