CircleCI is the third continuous integration system which is supported by the build history chart now. AppVeyor and TravisCI are the other two. If you have a public open source project which is built by one of those systems then you might want to check out the official documentation for the build history chart. Its quite cool and lets you create SVG badges like the one I did for my blog:
On a complete separate note I also added a new SVG badge for NuGet packages.
I did not think of adding NuGet support in the beginning, but since Shields.io NuGet badges are broken for more than 2 weeks now I had to look for an alternative:
The issue has been reported, but it doesn't look like it will get fixed any time soon and so I went with my own solution.
For my personal projects I like to display the current version of my NuGet packages as well as the total number of downloads. With Shields.io I had to use two individual badges, but with Buildstats.info I can display both in one:
This is a first version which satisfied my own personal needs, but will likely expand over the next coming weeks providing more functionality for other users as well.
I have a few ideas, but if you are looking for something in particular then please feel free to file a feature request on the public GitHub repository.