OK, probably one of Charles's least practical aliens, Nevermore, who will be the first additional and will appear in "Ix This." Not only does he mostly say "Nevermore," but he is very unlikely to see the plan that's right under his nose, due to this form's idiosyncratic, mainly negative thought patterns. So I'm going to include him. Overflow, see Overflow. Stinkfly. Sableye, think the Pokemon Sableye, repurposed as an Omnitrix alien. The Polytrix version is a talking Sableye. Rocks. Maybe even Portaler.