You can use canva as well!

As teachers we need to motivate our learners. After every class, the teacher can send a card, by mail (or whatever platform he wishes), saying "thank you" to his student (who participated actively). Teacher should assign a prize/ a reason why they are collecting, so that students would try to get as many as possible. Or, apart from the prize, it may help students to understand that you as their teacher care about their participation. 

This is just one modest suggestion! 

After negotiating with your learners, you can also give different kinds of feedbacks.