Over a few weeks in between live projects I have been working on getting convincing rain trails on glass for a logo design/animation I am putting together for myself. It's done in Blender 2.9 also using a progammatic add-on called Animation Nodes plus a smidgen of python. It's taken some figuring out as I'm a Blender noob on a steep learning curve! Great that one can imagine something then eventually get it to look like that!
Raindrops (developmental)