Below is a complete list of commands, also known as CMD commands, available from the Command Prompt in Windows 7, as well as Windows Vista.
ARP: Used to display or change entries in the ARP cache.
ASSOC: Displays or modifies file extension associations.
ATTRIB: Displays of changes file attributes.
BREAK: Sets or clears extended CTRL+C checking.
BCDBOOT: Used to copy critical files to the system.
BCDEDIT: Sets properties in boot database to control boot loading.
CACLS: Shows or changes access control lists (ACLs) of files.
CALL: Calls a batch program from another.
CD: Shows the name of or changes a current directory.
CHCP: Displays or sets the active code page number.
CHDIR: Displays the name of or changes the current directory.
CHKDSK: Checks a disk and displays a status report.
CHKNTFS: Displays or modifies the checking of disk at boot time.
CHOICE: Batch file command that allows users to select from a set of options.
CIPHER: Displays or alters the encryption of directories (files) on NTFS partitions.
CLIP: Redirects output of another command to the Windows clipboard.
CLS: Clears the screen.
CMD: Starts a new instance of the Windows command interpreter.
CMDKEY: Creates, lists and deletes stored user names and passwords or credentials.
COLOR: Sets the default console colors.
COMP: Compares the contents of two files or sets of files byte-be-byte.
COMPACT: Displays or alters the compression of files on NTFS partitions.
CONVERT: Converts FAT volumes to NTFS. You cannot convert the current drive.
COPY: Copies one or more files to another location.
DATE: Displays or sets the date.
DEFRAG: Disk defragmenter accessory.
DEL: Deletes one or more files.
DIR: Displays a list of files and sub-directories in a directory.
DISKCOMP: Compares the contents of two floppy disks.
DISKCOPY: Copies the contents of one floppy disk to another.
DISKPART: Displays or configures Disk Partition properties.
DOSKEY: Edits command lines, recalls Windows commands, and creates macros.
DRIVERQUERY: Displays current device driver status and properties.
ECHO: Displays messages, or turns command echoing on or off.
ENDLOCAL: Ends localization of environment changes in a batch file.
ERASE: Deletes one or more files.
EXIT: Quits and closes the command shell.
EXPAND: Expands compressed files.
FC: Compared two files or sets of files, and displays the differences between them.
FIND: Searches for a text string in a file or files.
FINDSTR: Searches for strings in files.
FOR: Runs a specified command for each item in a set.
FORFILES: Selects files in a folder for batch processing.
FORMAT: Formats a disk for use with Windows.
FSUTIL: Displays or configures the file system properties.
FTYPE: Displays or modifies file types used in file extension associations.
GOTO: Directs the Windows command interpreter to a labeled line in a batch program.
GPRESULT: Displays Group Policy information for machine or User.
GRAFTABL: Enables Windows to display an extended character set in graphics mode.
HELP: Provides Help information for Windows commands.
ICACLS: Display, modify, backup, or restore ACLs for files and directories.
IF: Performs conditional processing in batch programs.
IPCONFIG: Displays all current TCP/IP network configuration values.
LABEL: Creates, changes, or deletes the volume label of a disk.
MD: Creates a directory.
MKDIR: Creates a directory.
MKLINK: Creates Symbolic Links and Hard Links.
MODE: Configures a system device.
MORE: Displays output one screen at a time.
MOVE: Moves one or more files from one directory to another directory.
OPENFILES: Queries, displays, or disconnects open files or files opened by network users.
PATH: Displays or sets a search path for executable files.
PAUSE: Suspends processing of a batch file.
POPD: Restores the previous value of the current directory saved by PUSHD.
PRINT: Prints a text file.
PROMPT: Changes the Windows command prompt.
PUSHD: Saves the current directory then changes it.
RD: Removes a directory.
RECOVER: Recovers readable information from a bad or defective disk.
REM: Designates comments (remarks) in batch files.
REN: Renames a file or files.
RENAME: Renames a file or files.
REPLACE: Replaces files.
RMDIR: Removes a directory.
ROBOCOPY: Advanced utility to copy files and directory trees.
SET: Displays, sets, or removes environment variables for current session.
SETLOCAL: Begins localization of environment changes in a batch file.
SETX: Sets environment variables.
SC: Displays or configures services (background processes).
SCHTASKS: Schedules commands and programs to run on a computer.
SHIFT: Shifts the position of replaceable parameters in batch files.
SHUTDOWN: Allows proper local or remote shutdown of machine.
SORT: Sort input.
START: Starts a separate window to run a specified program or command.
SUBST: Associates a path with a drive letter.
SYSTEMINFO: Displays machine specific properties and configuration.
TAKEOWN: Allows an administrator to take ownership of a file.
TASKLIST: Displays all currently running tasks including services.
TASKKILL: Kill running process or application.
TIME: Displays or sets the system time.
TIMEOUT: Pauses the command processor for the specified number of seconds.
TITLE: Sets the window title for a CMD.EXE session.
TREE: Graphically displays the directory structure of a drive or path.
TYPE: Displays the contents of a text file.
VER: Displays the Windows version.
VERIFY: Tells Windows whether to verify that your files are written correctly t a disk.
VOL: Displays a disk volume label and serial number.
VSSADMIN: Volume Shadow Copy Service Administration tool.
WHERE: Displays the location of files that match a search pattern.
WMIC: Displays WMI information inside interactive command shell.
XCOPY: Copies files and directory trees.
XWIZARD: Is used to register data in Windows, often from a pre-configured XML file.
I tried hard to include every single command available within the Command Prompt in Windows 7 in my list above but I certainly could have missed one. If I did, please let me know so I can add it.