For each of these fandoms, I listed the number of works, and the most common relationship category, character, fandom tag (for many it’s the same, but for the umbrella fandoms like “Marvel”, the top fandom tag is a subset fandom), freeform tag, rating, relationship, and warning.
I sorted the fandoms in order of number of fanworks on AO3. I looked at approximately the top 100 fandoms on AO3 (actually the top 96, due to some silly processing errors on my part – oops).
Please point out popular fandoms that you see missing! I will work to update this. What are the most common fandoms on AO3 right now? (Aug 2013) What are their most common traits? Caveat: due to processing errors, a number of fandoms did not get properly analyzed - mostly ones whose names contain Japanese characters, but apparently also Les Mis (and possibly others).
