RGraph is an Open Source JavaScript charts library built for websites. It was started in 2008 and was initially canvas only.
Now it has support for over 60 responsive chart types across SVG and canvas, multiple data source import capability (including CSV files, Google Sheets, AJAX and documentation for using server data), animations, JSON and AJAX support and more besides. RGraph is licensed using the GPLv2 and an inexpensive commercial license. When it was started in 2008 it used SVN for source control and was moved on to GitHub in 2021.
Links point to the RGraph website