the method is also good for ellipses

3d kinematik, use constrain, SolveSpace Sketch - Anywhere in 3D options:
https://www.youtube.com/watch?v=rI_kfiUpc3Y

> What would be an ideal "tool" for making gear teeth?

An ideal tool might a way to generate teeth with "approximated Involute curve" using just two tangentially connected Bézier curve segments constrained in a place of left (or right) teeth side:

- https://www.arc.id.au/GearDrawing.html

Then flipping these two segment across teeth axis would create left and right sides of teeth and adding other arcs and rounds might be trivial made by hand.

Here is an example of setting such "approximated Involute" teeth profile in SolveSpace:

- https://fosstodon.org/@app4soft/109852258253299248

And here is an example of resulted gears 3D assembly tolerance quality:

- https://youtube.com/watch?q=W0KIwkXv030

Using this way decreases number of entities and constraints needed for single teeth construction, and same time produces high quality Involute-like smooth teeth profile good enough for any DIY work.