When it comes to libraries, though there are no standard libraries in C ala C++ or Python, there are a rich variety of open source libraries written in C which have been time-tested and proven to be efficient and effective. For example, libraries like libcurl, libxml2 etc are commonly used in multiple applications. Also, there are multiple utilities which come prepackaged with the GNU and Linux operating systems like grep and make, which are essential for both developers and users.
One of the other advantages of C is that it has very little run-time overhead, given that it is “one step above assembly”. This results in code which runs relatively fast. Needless to say, the memory and algorithmic optimizations are mostly up to developers. But, comparing apples to apples, running the same algorithm in C is usually much faster than in Python.