I find IPE to be a life-savior when it comes to generating physics illustrations which come with their share of math toppings. The editor has nice utilities for latching on to the boundaries, intersection, center etc of geometric figures. The spline tool is the best I have seen anywhere. Layers are handled with grace. LaTeX is rendered instantly. It is very easy to produce a multipage document. What more can one possibly want?
Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
Sketch - Professional digital design for Mac.
LaTeXDraw - LaTeXDraw is a graphical drawing editor for LaTeX.
Adobe Illustrator CC - Adobe Illustrator CC is a commercial vector graphics editor.
draw.io - Online diagramming application
Adobe Illustrator - Adobe Illustrator is a vector graphics editor.