Over at Oliver Ladeuix’s site, he just recently updated an older post he had written about wanting to become a rigger and many of the thoughts you should consider while undertaking that path. Many of them I feel are important from an animators perspective as well. Understanding the functionality of rigging and what ultimately will be user friendly to the animator will make each workflow better both animation and rigging. I also feel that the collaboration between rigging and animation should be a close one during development, otherwise both can continue to struggle with changes and issues during production. He lays out a bunch of great references.
I’ve always looked at Victor Vinyals rigs as a great standard! Click on the image to check out his stuff.
This great example of a rigging tool from game studio Epic.