Deliver lessons with Unio

Unio is a free platform for creating lessons and delivering them directly to your students’ laptop screens. It’s designed to let you project a lesson and quizzes onto your students’ screens and have them follow along with you. You can include quiz questions at various points throughout your lessons.

Source: Free Technology for Teachers: How to Use Unio to Deliver Lessons to Students’ Screens

They have a free and paid tier, it looks pretty cool! On their Using Unio in Class there are a few movies to get you started.