Uncountable times I just need a variable quickly to do some calculation or count something etc. Especially within loops that I abuse as functions this is the case.
Mostly I end up using global variables for it because they can be named so nicely.

It'd be cool to have an object that takes care of temporary variables that you can specify with a string as the name to make the code more readable.

Example:
I want to count how many of object "A" have their flag 0 on. I have a "temporary variable object" called "Temp".

+ Always
> Temp > Set "count var" to 0
> Start loop "countem" NObjects("A") // which are numbered

+ On loop "countem"
+ Value A of "A" is loopindex "countem" etc.
+ Flag A of "A" is on
> Temp > Add 1 to "count var"

+ Always
> Jump to frame Temp("count var") // or whatever


This would probably be a nice extension for a beginning extension developer, as it'd excel in simplicity while being horribly useful.