Ren'Py is a popular engine for these types of games because it:

Games often developed by small teams or individual creators. Understanding Ren'Py

Most games include built-in saving, loading, and "rollback" (the ability to go back and see previous text) by default.

The Socigames page you are looking for likely features a collection of visual novels and interactive stories built using the Ren'Py Visual Novel Engine .