Supporting ongoing microstock imagery and arranging files so they draw in viewers is a key skill. You may want to submit your portfolio to another person and see which images they pick out as your strongest. Your perception that you are a killer sports photographer may not find resonance with the person doing the critique. Your area of strength may be woefully gelected.
There are always low cost legal image markets you could be specializing in. Food photos for low cost legal images are an excellent example, for recipes, blogs and cooking sites. It is expecially strategic when you everyone in the microstock markets is zigging and you decide to zag. In photography terms, if the whole online microstock photography populaton is submitting mad space to files of sports images and pharmaceuticals, it’s time for you to get ocean image file shots and food markets.
Now, to market. The market for things like this can be large because often people are simply looking in image searches for what something looks like. Rarely will anybody look through a 5,000 Wikipedia article when they can scan a few images and make up their minds for themselves. The tags that accompany the image will bring the traffic. Unfamiliar words or proper styles or definitive design or art detail gets curiosity traffic.