They are all part of the Bentley MX Tools download which is what MX Bonus Tools used to be called and is available from Enhancements and updates for Bentley MX.
The latest version of Bentley MX Tools currently available is Bentley MX Tools V8i - 08.11.05.02. These will also work with Bentley MX V8i SS1.
If you do not see infraTools in Add-Ins>Personal Addins menu then I would suggest uninstalling MX Tools and then reinstalling, making sure you choose to install the AU Tools which is what the infraTools are.
Jim Irvine TSG Civil