TNG Era Ships (2355-2370)
The TNG era features no considerably different designs than the preceding mid-24th century on one hand and the subsequent post-TNG era on the other hand. Most obviously, it marks a transition from the elliptical saucer and rounded hull shapes to more variety in design approaches. Generally speaking, the single ship designs are getting more distinctive. It has to be mentioned that although I call it the "TNG era", no design of this era actually appeared in TNG, but ships like the prototype U.S.S Bradbury with its NX number denoting a prototype were only mentioned.
However, there are the ship classes from "Star Trek VIII" (Akira, Norway and Saber) and Star Trek Voyager (Nova) as perhaps typical representatives of the TNG design era. With their registries below NCC-70000, the ship designs could even precede the TNG era, but given their "modern" appearance they were most likely developed in the 2360's. The Akira class still sports the elliptical saucer similar to the Galaxy's, while the Norway and Nova have rather triangular and the Saber an irregular main hull. Other features, from the main arrangement to small details, are also subject to vary considerably.
It can be supposed that all these ships achieve top speeds of at least Warp 9.2. Their registries range from about NCC-65000 to NCC-74000.