To get the list of all the commands installed in the system use the below command line. It will include all the Alias, Functions and Cmdlets.
To export them into the CSV file,
Get-Command | Export-Csv D:\Temp\PowerShellcommands.csv - NoTypeInformation
To get only the cmdlets commands,
Get-Command -CommandType Cmdlet
Similarly, you can get the commands for the alias and functions.
If you want the list of commands starting with getting, you parameter –Verb.
Get-Command -Verb Get
To get command starting with Set,
Get-Command -Verb Set