Web interfaces are constantly evolving and so there is constant evolution in this space. There are a number of noteworthy Python packages that integrate into the PyData ecosystem that are more narrowly focused than pandas-datareader.
Alpha Vantage provides real time and historical equity data. Users are required to get a free API key before using the API. Documentation is available.
A python package simplifying access is available on github.
Tiingo aims to make high-end financial tools accessible investors. The API is documented. Users are required to get a free API key before using the API.
A python package simplifying access is available on github.
Barchart is a data provider covering a wide range of financial data. The free API provides up to two years of historical data.
A python package simplifying access is available on github.
Awesome Quant maintains a large list of packages designed to provide access to financial data.