The listenc command lists all encodings implemented in .Net. This will display the code page, name, and display name of all Encodings.

listenc | find "Unicode"

returns

 1200 utf-16                  Unicode
 1201 utf-16BE                Unicode (Big-Endian)
12000 utf-32                  Unicode (UTF-32)
12001 utf-32BE                Unicode (UTF-32 Big-Endian)
65000 utf-7                   Unicode (UTF-7)
65001 utf-8                   Unicode (UTF-8)

The list ist sorted by the code page (CP) by default, and can be changed using the -o switch.