Not sure what you are looking for. Some people really like mind mapping, though I have not tried it.

I find it helps to organize information in a tree structure. This is a freeware tool that I have used. It might work in looking for creative ideas.

I have sometimes found solutions to problems by having a written conversation with myself. There might be some problem that I am trying to solve and I might write something like “What if….” After thinking about it for awhile I might write, “That won’t work because…, but it might work if instead…”

Thanks, @LostInParadise. That looks like it could be useful.

I’ve also used FreeMind.