Powtoon is a free tool for creating animated videos and presentations. A variety of tutorials for getting started with Powtoon are available.
Vyond is another free tool for creating animated videos. Tutorials are available on the blog.
3D graphics software refers to programs used to create 3D computer-generated imagery. This imagery is used in animation, video games and commercial illustration.
Blender is an free open source 3D content creation suite, available for all major operating systems. It is a powerful application with a distinct learning curve.
Blender's user manual is available online in a wiki format, and is constantly updated. This set of tutorials is suited to the beginner.
Sketchup was formerly owned by Google. The large user-base makes Sketchup an attractive option.
There is an impressive amount of free training videos on the Sketchup site. There are videos suited to all levels of user skill, as well as a few self paced tutorials.