Drop to GIF - Super simple movie to GIF conversion
ImBatch - ImBatch is a batch image processor with a nice graphical user interface.
GIFMaker for Mac - GIFMaker – Created a GIF from a video or Images is the easiest way to create an animated GIF on your Mac.
DVDVideoSoft Image Convert and Resize - Free Image Convert and Resize is a compact yet powerful program for batch mode image processing.
Giphy - Search all the gifs and make your own animated gif
Batch Image Resizer - Resize, crop, shrink, flip, exif-rotate, convert, enhance, process multiple pictures and photos with professional software! 120+ Actions, 30+ Image Formats