You can practice off of the one Stan did (I think most people do it to better understand the assignment). The course doesn’t include reference images, but there are model packs you can purchase from Proko. If you’re looking for some timed figure drawing references online, I found that line of action (https://line-of-action.com/practice-tools/figure-drawing) and quickposes (https://quickposes.com/en) are good ressources.