AniView is a simple open-source animated GIF viewer.

Import any GIF via File > Open and the program plays it immediately (there's no drag and drop support, unfortunately.)

Large "left" and "right" buttons enable stepping through and viewing any GIFs in the same folder.

There are menu options to export all animation frames, open the image in your default GIF editor, or view Explorer's Properties dialog for the file.

A Settings dialog has options for "Repeat behaviour" (play the animation one, twice, three times or repeat forever), and your preferred export format (PNG, BMP, JPEG and TIFF, though not GIF, surprisingly).