The Federation Class is from the Star Trek Technical Manual, written by Franz Joseph. Although there was a falling out between Joseph and Roddenberry, the diagrams from the book were shown on screen during the first six movies, which makes the ships canon in my opinion. That said, there’s no evidence for a refit version, and I’ve altered the designs a bit so I’m sticking them in this category.
Keeping with the Tech Manual, I made this version 50% larger then the Constitution Class, and I’ve armed it with 20x phasers, and an extra pair of rear facing torpedoes. This design doesn’t exist in my personal fleet, having been replaced by the Ulysses and Kanazawa classes.