If you want a single free tool that can do just about anything video editing related, you should look at Davinci Resolve. It is available on Linux Mac and Windows.
If you are going to do anything 3d look at Blender, also available on all three major platforms. Both are free, but Davinici is more video and colour correction oriented and Blender is more 3d rendering oriented. Blender will take longer to learn.
You will need a powerful computer with plenty of storage for any major video project.
