Measurement transform (directly change the size of the selected edge) and color - please change and make text size editable - User Feedback - Blender Developer Talk
Dimension. Addon for blender 2.79 and 2.80 to measure distance, angle and add description.
objects - How do I measure a distance between two points? - Blender Stack Exchange
bezier curves - Measurement of the "Straightened" length of a path - Blender Stack Exchange
How to get scale measurements in Blender 2.79
How to get scale measurements in Blender 2.79
How to Use the MeasureIt Add-on in Blender – Discover Learn Create
MeasureIt, Display Distance in the Blender Viewport - Lesterbanks