Drizzle
Drizzle is a multipurpose toolkit. Among its functions are the management of Fan Ages, and the integration of various Cyan games with the Uru: PotS game engine.
Drizzle is available at SourceForge, and information regarding its use can be found in the Drizzle article of the Alcugs wiki.
Tabs
Different tools included in Drizzle are separated into tabs.
UruAgeManager
This tool handles downloading and installing Fan Ages.
Simplicity
This tool is used to convert Ages (from Myst Online: Uru Live, Myst 5: End of Ages, or Crowthistle) for use in the Uru: Path of the Shell version of Plasma. A copy of the game you're converting is required.