schwab-login
Logging into Charles Schwab account for automation
The other packages I found were old/outdated as of 2018-03, so I here's a simple (proof of concept) using Python 3, Selenium and headless Chrome.
NOTE: Currently more of a sketch than anything production oriented but should help someone looking to implement something more robust so sharing (may refactor into something more useful later)
You might be better off getting a https://plaid.com/ Developer key.
See also: