These are OC ships, like the captains; I wanna try more art in the new year, but it can be slow, so it's a secondary priority. Descriptions are very doable!
The Bubo-class is easiest to describe because it comes straight from a movie; in the background of First Contact, the VFX team from ILM leaved a little calling card in the form of a little, fuzzy Millennium Falcon! To turn it into a Trek ship, I assumed it was out-of-scale, ignored the asymmetrical cockpit, and flipped the whole thing around; scaled it to be roughly the same size as the Protostar, the mandibles became the nacelles, and the bridge went over the top turret. It's a Tellarite-made convoy escort that mostly handles moving personnel and cargo between Starbases.
The Galileo-class is my take on a vertical saucer; take a Galaxy-class saucer, shrink it a lot, then stand it on one of its narrow points like a football. Attach an in-line engineering hull at the back, then hang a pair of scaled Miranda nacelles off the side - whole thing is roughly as long as a CR-90 from SW. This one is about handling expeditions; the saucer and nacelles have retractable landing gear so the corvette can land on a planet's surface. It's somewhat fragile and high-maintenance, however, so Starfleet is slowly chipping away at a replacement.
The Peregrine is an Andorian design; take the Andorian battlecruiser from Enterprise and replace its nacelles with the Connie refit's and you're basically there. She's a swift response craft built by the Andorian Royal Guard to test out a new model of rapid-fire torpedo launcher that's become standard-issue within Starfleet.