To get the range 01-25 with A..D prefix you can use this: [A-D](0[1-9]|1\d|2[0-5])
Explained demo here: http://regex101.com/r/gU3zA4
This: [A-G](0[1-9]|1\d|20)
will get A-G from 01 to 20
This: [A-Z](0[1-9]|[1-6]\d|7[0-5])
will get A-Z from 01 to 75
This: [A-Z](0[1-9]|[1-9]\d)
will get A-Z from 01 to 99
Pretty easy...