You can choose from the 511 games from "Classic Baseball Radio Broadcasts MLB" from https://archive.org/details/classicmlbbaseballradio/. The games are public domain and available for anyone. The archive includes game from 1934 to 1973, including many World Series Games and All Star Games. The audio quality and output volume varies.
This skill makes the archive available to play directly using any Alexa device. There is currently no pause/play functionality or an ability to save your current location in the audio stream. If you pause or stop you must restart the game from the beginning.
As I learn more about programming for Alexa I hope to add these and more features.