Here is a list of tools we can use to make trailers. 

I movie

http://www.apple.com/imovie/

Puppet pals:

https://itunes.apple.com/us/app/puppet-pals-hd/id342076546?mt=8

Pow Toon:

https://www.powtoon.com/

Canva

https://www.canva.com/

Adobe Spark

https://spark.adobe.com

Animoto

https://animoto.com/

Tellagami

https://tellagami.com

Genial.ly
https://www.genial.ly

Kizoa.fr : online video maker using photos, videos and music. You may add text, special effects and transitions

https://www.kizoa.fr/

Learningapps.org :  a very simple tool to built games for our friends. Available in 21 languages.

https://learningapps.org/

Jigsawplanet.com : to make wonderful puzzles for free without any add.

https://www.jigsawplanet.com/

Naturalreaders : a quite good tool (one of the best at the moment for me) to let your text be read in a foreign language if the kids are ashamed to speak :o)

https://www.naturalreaders.com/

The best translator at the moment but only a few languages available : deepl.com 

https://www.deepl.com/translator

AnimateAnything, or Photospeak, apps to let a picture speaks, e.i. on a book cover

To make a book and and read it : https://www.storyjumper.com

A lot of very good free (CC0) pictures for our school work :

http://www.photosforclass.com/

https://www.flickr.com/commons

https://pixabay.com/

https://www.pexels.com/

https://kaboompics.com/gallery

https://unsplash.com/

https://negativespace.co/

https://gratisography.com/

thinglink.com

https://www.thinglink.com/scene/1032301860217683971

Biteable is a video creation tool that offers students unending creative options for expressing what they know.

https://biteable.com/blog/inspiration/creative-video-project-ideas-for-students/