Padlet is one thing we’ve used over the past year, particularly Nick and myself in our B2, C1 and C2 groups.
I found it on a teacher training site, where the idea was to use it for brainstorming. This works really well for making sure everybody is stimulated to speak much more in online classes. But by playing around with it, we’ve found more ways to use Padlet to give us more interactive, creative lessons.
Maybe you’ve done listening exercises in class with cut-up lyrics to put in order. Have you ever done in online? Probably not, but we’ve used Padlet that way in our classes and it works.
What about a vocabulary exercises where you sort out words and phrases into categories? Try this activity I made for B2 FCE groups. Click on the phrase and drag it to the right column.
https://padlet.com/robpagett/1f1n1p7m71o7vlf7
Dominoes for learning and practising collocations? We’ve done that and it works, too. 
Conditional exercises where students are practising and learning through creating their own Padlet examples? We’ve done it in our classes as well.
https://padlet.com/robpagett/e9tnf4jy7poqfk24
Being the enthusiastic types we are, we’re looking for new tools all the time to make this year’s online classes fun, useful and varied.