is there a way we could get the Hoyle as well as the Sierra Discovery Series games on GOG.com

In short: Probably not. Educational software is a beast to track for, and card games are complicated, legally. They've been licensed, sublicenced and handed over to so many companies over the years.

For example, when you said "Hoyle", I thought of the MPV Software games, which is a company that went belly up some time ago. They do run just fine in ScummVM, but they might have to unbranded or something.

Still, don't give up hope. They're probably all listed in the GOG wishlist already.