Lateral thinking puzzles are a great quick filler. I started out using them as a filler years ago but they quickly became a daily favorite of my students. This would be easy to incorporate into zoom. Another idea that I think can be fun and challenging for student is sorting. Have students find one item near them and show the group, once everyone has shown their item, the group has to figure out a way to sort them, this can lead to some great discussions on how plants, animals etc are classified, and the students can come up with very interesting categories.