This is a paid asset, but now you can download Simple Particle Scaler Free.
Detail this asset from Unity Store: Original Link
Simple Particle Scaler v1.1.3 (Latest version)
“If possible, please buy the package to support the developer”
Simple Particle Scaler makes scaling particles easy, simply select one or multiple particles in your hierarchy and scale with a click of a button. This tool also enabled you to save prefabs of your newly scaled particles, so you don’t have to drag each one separately to your project.
∙ Scale Multiple Particle System
Scales all selected shuriken particle systems
∙ Save Multiple Prefabs
Creates prefabs from selected GameObjects
The tool is located in “Window/Simple Particle Scale”
Demo video uses asset Liquid Particles
Compatible with Unity 5.1 up to new versions of Unity(2020+)
Support available for assistance if any problems should occur.