Synfig Studio is a 2D animation tool that uses both vector and bitmap graphics to eliminate the necessity of creating animations frame by frame and allows you to work faster and with fewer resources.
Thanks to all the elements that are created in the programme itself being vector based, the only pixilation that you will experience when you change the resolution or size, will be from the imported images, something that you can do with surprising ease.
The programme supports various caps: geometrics, gradients, filters, conversions, and many more. All of them can be controlled from the program interface. However, it will require some expertise on your part to take advantage of all its possibilities.
Synfig Studio is a very comprehensive application that, fortunately, has a complete online manual on the author´s website. With this, anyone can, with a little bit of patience, create their own animations.