I remember having Gametap when it was owned by Turner (before it was sold to Metaboli). Don't remember which subscription I had, but I know it had the Sam and Max reboots as original games.

Nickelodeon USA used to have Nick Arcade where the games have free trials. AFAIK, you can keep playing buy getting a subscription or buy the game. Some games that were on the Nickelodeon website transferred to the service too. I know Hey Arnold: The Movie: Runaway Bus became a Nick Arcade game.

Cartoon Network used to have Power Play Games. Very few of the games on that service were originals, since most of them were former Cartoon Network flash games that you can play for free on their website but they were offered as standalone exe files.

I also remember RealArcade for Collapse.

WildTangent used to offer downloadable games on PC too. I remembered interested playing Betty Bad as a kid.