The most interesting ones are the ones with regular polygons for faces, and that are higher in symmetry than prisms. I am working on coming up with a nice collection of them based on the works of B.M.Stewart. In the meantime, I have a set below that got me started on the subject. (Note: this page was originally created way before I got a copy of Stewart's book Adventures Among the Toroids)
I found a page on George Hart's site on the subject of toroidal polyhedra, that included a great figure of a Rhombicuboctahedron inside of a Truncated Cuboctahedron, connected by squares and equilateral triangles. Certain faces were removed (systematically) so that there were no more than 2 faces meeting at any given edge. I wanted to see what would happen to the corresponding figures in the tetrahedral symmetry group and the icosahedral symmetry group.
Below are the non-regular-faced toroidal polyhedra that I discovered. I plan to add some of the regular-faced ones I have found, once I have put together a nice collection.
Icosahedral Symmetry Group - Rhombicosidodecahedron in Truncated Icosidodecahedron
There are many other toroidal polyhedra that merely have prism symmetry. I will probably be building some of these eventually, but I do not find them as interesting as those with higher symmetry.
Most of the work on this page was inspired indirectly by Bonnie Madison Stewart's book, Adventures Among the Toroids. I finally have a copy of the book, so I am sure you will see some more toroidal polyhedra on this site in the near future.