Derelicts come in many shapes and sizes. They are classified in a Range from A1 to C10. A1 being the smallest of the type and C10 being large structures like battleships or large orbital stations.
Derelicts can be located in almost any place where humanity has traveled, although you will require the correct scanning equipment to locate them. There are currently three scanners available to the public.
These are player crafted and range from the smallest Derelict System Scanner T1 to the largest Derelict System Scanner T3. Each scanner has the ability to locate derelicts within its scanner class.
The T1 will scan for derelicts from A1 to A10.
The T2 will scan for derelicts from A1 to B10.
The T3 will scan for derelicts from A1 to C10.
Note: These scanners use 5 fuel to activate and scan a location of space. They cannot be used in orbit of a jump-gate.