You asked us, and we delivered! Our collection of free animated icons now includes animated GIFs with transparent backgrounds.
You can download them in the archive with the rest of the files.
P.S. The edges in transparent GIFs may appear pixelated. It is a feature of this raster format, so bear with us and use GIFs with a white background or Lottie animations when possible.
About the author: Margarita Ivanchikova, graphic and motion designer for Icons8