I checked for you in regard to your Sheppard Software, and found some information on their contact page which may be helpful: http://www.sheppardsoftware.com/contact.htm. It looks like they are in process of converting some of the games and programs. They are also recommending that you contact Adobe to request a converter for Flash games. Unfortunately, the games won't automatically work using HTML5 because they have to be updated/upgraded to run properly in another language like HTML5. The website would have to update and republish their games in a different output other than Flash to remedy the situation. You can also look into some alternative websites. I did a search on "best educational games" and found quite a few matches like https://www.abcmouse.com/ or what about https://pbskids.org/games/ ? I'm an Instructional Designer and I have an educational coloring and activity book coming out very soon. If you want a sample, please message me. I'm also considering creating a 2nd YouTube channel for kids with fun videos and activities (my current one is most for technology software training). Let me know what you are interested in as I'm looking for ideas of what to create.