This document provides an overview of exoelectrogens, or electrogenic organisms that can transfer electrons outside of their cells. It outlines various bacteria, archaea, algae, fungi, plants, and animals that have this ability, including specific organisms like Geobacter, Shewanella, cyanobacteria, Pyrococcus, Chlorella, Rhizopus, and plants like moss, rice, and fruits. The document also mentions synergistic relationships between different microorganisms like bacteria and algae that can work together to transfer electrons outside of their cells.