I often create GIFs from a consecutive sequence of transparent PNGs (exported from a 3D modeling app).
My current workflow is:
1-Export the animation from the 3D app (Blender) to transparent PNGs
2-Import the PNG sequence into After Effects
3-Export to Lossless RGB + Alpha from After Effects
4-Import the resulting file into Photoshop
5-Save for Web from Photoshop as a GIF
I find the workflow to be a bit long and tedious.