Here are some tools I’ve used for creating various 2d diagrams:
Math Illustrations – create and label all sorts of 2d pictures with shapes, angles, etc. Takes a little bit of exploring but very user friendly given the prevision with which it can create good diagrams. Downsides…it’s not free but there’s a free trial to play around with and it’s not too expensive at time of writing.
Geogebra has lots of free tools for geometric diagrams, graphs and more.
Desmos is hard to beat for a free graphing tool.