Recently discovered Vassal and Tabletop Simulator. They are applications that allow you to play "cardboard" games online. They provide a digital playing platform. So, in most instances no AI or rules enforcement. Just provides a digital platform where you move counters/cards/roll dice etc, talk with an opponent or talk to yourself! I know that TTS has a bunch of games available for free, many of them contemporary, and others where you can pay for DLC.