What do all of the different cloud icons mean?

I am trying to sync my computer through google drive. Often these symbols appear next to folders and files and I would like to understand exactly what they mean, and when I will see them. Surely there is some big list of the definitions of each symbol? 1. Blue and white cloud: 2. Empty cloud: 3. Empty cloud with arrow: 4. Dotted cloud: 5. Green checkmark: 6. Red exclamation mark 7. Nothing (even when inside a folder with one of the other symbols, or a folder containing files with one of the other symbols) 8. Looks like I can also have multiple of these: (blue and white cloud + empty cloud): Probably there are others, but I'm just surprised to keep encountering new symbols I haven't seen, and I really want to understand the technical meaning behind them.