It looks like the common component across the apps mentioned is in the "net.shinhwa21.jsylibrary" namespace.

I made a list of the apps with that namespace, preview here: https://mixrank.com/playstore/apps?expiration=2017-06-30&lis...

This list is a few times bigger than the ones mentioned in the article (been crawling for a long time, and try to be complete). If there's any security folks here that want access to the APKs for research, I'm happy to share (scott at mixrank).