Leveraging the color palette used by Google Visualization
I have used colors from the Google Visualization default palette for several projects. You can quickly generate all colors using a simple code below and pick those colors and save for yourself.
If you don’t have a way to extract RGB codes, here it is. The order is blue, red, orange, green, purple, and so on. Although I giving you about 20 colors here, I personally try not to go beyond 5–6 colors at the most. The colors in this list beyond that threshold seem to start repeating itself.