I am making categories and subcategories in a folder and I am trying to keep the tags to one word if possible. "Unstarted" is all I can find online and it just doesn't sound right to me.
If I've interpreted correctly, you want a word describing something that you have decided on, but not yet started. Per Collins Dictionary:
Unbegun: not commenced; not yet started; not having a beginning; always existing.
Unstarted/Unbegun all mean that you have not started to work on tasks you have in mind. However, once they are in your folder, that means you've already started to work on them by putting them in that category and they must be either finished or discarded in the future.
The 3 biggest categories for all tasks will be "something to start (it can be sub-categorized depending on priority/importance)", "work-in-progress (it can be sub-categorized depending on progress/priority)", and "finished or pending final approval".
"To-do-list" means according to Oxford Dictionary;
A list of tasks that need to be completed, typically organized in order of priority:
"Ideas"" might be considered for the category as it just means what is in your thought or you have come up with recently.
I would go for "To-do-list".
Todoist is a popular application which helps organize your tasks. I find this name simple and clear.
Here are a couple ways to say it, not as one word, but as an idiom:
in the hopper http://idioms.thefreedictionary.com/in+the+hopper
But for a short tag on a folder, you could use an acronym such as
TBD (To Be Determined/Done)
TBA (To Be Arranged), that is, the time to start the work has yet to be arranged)