This filterable gallery of examples for D3.js is an alternative to the official wiki gallery. Filtering makes it easier to search by author, visualization type and so on. You can also share the url to a filtered result gallery. (From the DashingD3js.com Weekly Newsletter.)
Don’t be discouraged on the author filter, not all the visualizations are from Mike Bostock.
It is a real visual treat. Take the time to visit even if you aren’t looking for that “special” visualization.