Giv is a free GIF viewer.
The program isn't intrusive, and doesn't take over the GIF file association by default. But if you use it to open a GIF, then this is displayed, or played if it's animated, and you can start or stop playback again with a click.
Clicking Back/ Next buttons, or pressing the arrow keys on the keyboard, displays the last or next GIF in the same folder.
A right-click menu displays options to save the current, or all frames.
This all works well enough, and is easy to use, but there are a few irritations. We can't see any way to step through the animation one frame at a time, for instance. And extracted frames are saved as PNG files, which may be annoying if you need to use GIFs.
A simple GIF viewer which does a good basic job, but has plenty of room for improvement.