Not sure there are similar tools to the extent of this, certainly not Scrivener. Different capabilities, different audiences, different price points.

Still, this offers a free version which -- from my quick look -- can meet a lot of needs. Use it for planning & Scrivener for the writing. It also has a monthly option which can make it fairly reasonably-priced if you only subscribe as needed, using the free version in-between.

I'd add the hope that the Scrivener folks could add something like this to Scapple but that's clearly futile since their programmers seem way too challenged for something this advanced.