Canon wise, what known derelicts are floating around space circa 3025. I count two thus far.
FSS Pleiades - This New Syrtis class Carrier was retired in the Novaya Zemlya system during the Second Succession War after having its back broken by a return jump. (Historical: Reunification War pg. 220)
DCS Togura - This Samarkand class Carrier was the only one of its kind to survive to present and barely serves as a museum piece orbiting New Samarkand. (Technical Readout: 3075 pg. 216)
Just wanted to post this as food for thought. These two derelicts are clearly beyond salvage but did survive to 3025 and beyond. Pretty interesting to me and indicates there could be other space wrecks floating around out there.