With your skillset, you could be doing invaluable work by writing documentation.
The world is full of good Free software that is essentially orphaned, because the documentation is practically useless. Many moribund projects could be revitalised with little more than a concise description of what the software does, why you might choose it over the alternatives, and how to get started.
Other projects suffer from dreadfully myopic documentation, with a wiki full of detailed descriptions of weird minutiae, but little that would be of use to newcomers. Few developers can write well, and even fewer have the insight to view their project from an outsider's perspective.