LEGO Movie Maker: a free app from LEGO, it helps kids make stop motion movies with step-by-step guide, from take pictures frame by frame, to putting it together with music. It is a fun one for kids of any age.
GoldiBlox is another free app that young children can use. With this one, kids not only can use photos they take, but also can draw pictures themselves, or use provided stickers.
Toontastic has been my all time favorite. It provides all the tools kids need to create a movie, kids can take photos and videos as footage material, or use the provided settings and characters. What is really helpful, it tells kids how to create stories. Not very long ago, the developer has set it as a completely free app. There is also a Toontastic Junior for younger kids, which is also free.
Tellagami is a great tool for short movies or journals. Kids choose a character as their reporter and they type or narrate a short message for the reporter to present. Since there is a length limit, it is a good one for kids who just start making movies, as they won’t feel the presser of make a whole movie, they can just make scene at a time. It is a free app.
Shadow Puppet: kids can use pictures and videos from many sources within the app, the photo album of the device, and internet, institutes like some museums, they can then add music and narration. A very easy to use app. There is a free version of the app.
Explain Everything: has many features make it a wonderful tool for school study projects, and even teaching materials. Users can incorporate many different materials and the output can be exported to many different formats and cloud services. Kids can use videos, photos, drawings, notes, can add their own text and voice. All features are also flexible enough for many editing options.
DoodleCast is a live recording app, as I call it. It is mostly designed for you to draw and write and record the process, and you can add voices too. It is a good one for those who like to draw cartoons, although users can also use photos.
Sago Mini DoodleCast: similar to DoodleCast, but this one is designed for younger kids with many features that a preschooler can and like to use.
Educreation is another free app that kids can use with different sources materials to create videos. They can use photos, pictures, and record as they explain the content or tell the story.
Adobe Voice is a very easy app with very high quality images, and it is a free app from Adobe. Kids select pictures from the sources provided by Adobe or photo album on the device and create slides that build together to become a video. Kids can select music and add narration to the videos.