When exploring ideas for video or web it's common to lay out storyboards before going into production. Depending on the project, quickly putting those storyboards to motion can give stakeholders a better idea of pacing, messaging, and refinements needed before investing time and resources on final production.
Similar to web wireframes, it's important in the early stages to keep the visuals and motion abstract so decision makers can focus on concepts rather than style. Animatics are useful for media other than video too — banners, websites, and infographics where motion is important.
I like making rough motion tests with After Effects. After Effects is flexible, easy to use if you're already familiar with Adobe products, and quickly produces results. Below are three examples of, intentionally rough, animatics for a video concept.