Maybe one of these mini dungeons from AAW (AdventureAWeek.com)? 07: <a href="https://marketplace.roll20.net/browse/gameaddon/14" rel="nofollow">https://marketplace.roll20.net/browse/gameaddon/14</a>... 08: <a href="https://marketplace.roll20.net/browse/gameaddon/14" rel="nofollow">https://marketplace.roll20.net/browse/gameaddon/14</a>... 10: <a href="https://marketplace.roll20.net/browse/gameaddon/14" rel="nofollow">https://marketplace.roll20.net/browse/gameaddon/14</a>... 18: <a href="https://marketplace.roll20.net/browse/gameaddon/18" rel="nofollow">https://marketplace.roll20.net/browse/gameaddon/18</a>... 25: <a href="https://marketplace.roll20.net/browse/gameaddon/19" rel="nofollow">https://marketplace.roll20.net/browse/gameaddon/19</a>... 26: <a href="https://marketplace.roll20.net/browse/gameaddon/18" rel="nofollow">https://marketplace.roll20.net/browse/gameaddon/18</a>... 30: <a href="https://marketplace.roll20.net/browse/gameaddon/19" rel="nofollow">https://marketplace.roll20.net/browse/gameaddon/19</a>... I have not purchased any of their items on Roll20, but I have seen one of their mini dungeons in PDF form, and it looked like it would work as a one shot. They are only available as bundles at the moment. The 06-10 bundle would probably be the best bang for your buck.
