I've created a GUI to make creating effects easier and hopefully show how the Effect strings go together. Each effect can be edited via the magnifying glass which opens a secondary window.
You can find it here: https://forge.fantasygrounds.com/shop/items/457/view
For those that work on extensions, and want to look at the code I've hosted it here: https://github.com/SoxMax/FG-Effect-Builder
I tried to push functionality down into individual effect editors, this should allow for extensions to this extension that override the types of effects supported.
I've created plugins supporting rulesets here:
D&D 5E: https://forge.fantasygrounds.com/shop/items/463/view
D&D 3.5/PFRPG: https://forge.fantasygrounds.com/shop/items/464/view