Since timetravel has become an integral part of storytelling within the Star Trek universe, someone decided that Starfleet needed starship designed specifically for this purpose. And so I bring you today the U.S.S. Lynx, NCC -4600. Designed to fit within the original cast movie-era, warp capable despite the lack of warp nacelles, the Lynx Class is the Federation’s first dedicated timeship.
Getting back to canon for a moment, here is the original Saladin Class Federation Starship. She is a very simple design, single warp nacelle under the saucer, no secondary hull. It would have been nice to see this in an actual episode of The Original Series. These schematics and inboard profile were created at New Paradigm Studios.
Here is another non-canon starship found long ago, the Joshua Class Federation Starship. This looks like an Undiscovered Country-era version of the old Saladin Class, based on the similarities between it’s warp nacelle and that of the Excelsior Class. Included here is an internal diagram as well as a bridge layout.
Straying from canon for a bit, we bring you the Oppenheimer Class Federation Starship. This is an older design created by Jim Morvay. She is a sister class to the Excelsior. These are the only 2 views I have ever found.