Genially
If you've seen my Twitter and resources you will know I am a big Genially fan, and for good reason. The 'interactivity' that Genially offers sets it above many other products on the market. Combine that with a great interface, loads of free features and beautiful templates and you've got a winning combination.
Canva
If you haven't already heard of Canva then you probably will soon, it's gaining big popularity and for good reason. You can design a huge array of different media on Canva and most of the best bits are free. It also looks like a great product to get your students into learning, let them be creative, but also let them learn a product that they might use in work one day?
Book Creator
Book Creator ist exactly what it says, you can create your own books! In a very interactive sense. I had great fun making a little book with my daughter one weekend afternoon with book creator uploading some of her drawings and having her narrate what was going on :-)
Pear Deck
Pear Deck is a great way to upgrade your slides and make a move towards something more online/interactive. If you have lots of P-Points or G-Slides and you don't want to recreate things Pear Deck could be perfect. The 'prompts' would allow you to intersperse your slides with useful polls, text questions, multiple choice questions, activities etc.
Slidesgo
Slidesgo looks like a great place to go for inspiration. If you want to design some new slides with a fresh look, there are lots of templates on Slidesgo which may give you a great start point.
slidesMania
slidesMania is similar to slidego above, though the templates I found for lessons did not seem as comprehensive. However what I did really like is the section of their website called 'How-To's' which could be really useful for anyone.
Sutori
Sutori is a slightly different way of looking at lesson planning that I think is quite unique. It reminds me of padlet but is like a specific lesson creator off-shoot. It feels student paced, student centered. You work down the page through the activities that are interspersed with different interactivities, engagements, questions etc. My only thought is that the product feels quite new still.