Skip frames in rendering This might sound weird. I have a scene with alembic files. There are chunks in the timeline which do not need to be rendered. For example in a 200 frames timeline I want to skip say 20-51 and then 110-167. I cannot do this manually as I will be leaving my PC to render overnight and to save the render time I do not want to render the redundant parts. Is there a way to setup the file so that I render the parts I want from the timeline?
This addon called Loom is exactly what you need.
It allows you to specify ranges and specific frames that you want to render or skip. It's even possible to render every nth frame.

The addon allows to render single frames, multiple frame ranges as well as subframes, either directly within Blender's UI (as usual) or in a new terminal instance as background process in case you want to continue working while rendering.

From: How to render specific frames of animation