yEd

https://www.yworks.com/products/yed

One of our favourite editors - very good for drawing anything that's graph-like.

Add control points to edges

There are 5 types of edges:

• Polyline: Straight line(s)
• Arc: Curve with a single control point
• Bezier curve: Curve with multiple control points.
• Quadrative curve: Curve with multiple control points.
• Spline: Spline with multiple control points.

For the Bezier and Quadrative curves, it's possible to add new control points (bends) while holding the Shift key.

Default fonts

yEd's default font (Dialog) varies between systems. On macOS, it is (surprisingly) rendered with Lucida Grande.