Well first you need to remove everything on the card before you even do the reset, as well as remove the card from the tablet. The reason you need to clear the card first, is because of setting it up as "Internal" storage to run apps from. That becomes encoded. And while it 'should' still be readable by the phone after the reset, there have been many times I have seen it not work and all the data (not just games but all data) on the card becomes unusable.
In the case of most apps, you can just uninstall them, and then reinstall them after the reset. A hassle I know, but it would be the only way to do it without issue. You should be able to save your personal data from the games, and your other files on the card (not apps) to a computer. Just connect the tablet via USB cord and move all that over while the card is still in the tablet. Then, turn the card back to "External" storage and do your reset. You may also want to back up everything on the tablet itself. Contacts, etc., when you back up the rest.
You can try doing it without clearing off the card first, just be sure you don't leave the SD card in the tablet during the reset. However, remember there is a risk of losing access to all the data on it.