Another Freebase graph. The x axis is a listing of 1,000+ non-user types. The y axis is the number of topics in that type (log 10 scale, number of digits). The median is 39.5 topics per type. For instance there are 39 people listed as comic book pencilers and 40 building functions in the architecture domain. Up at the top are 4.1 million musical tracks. At the bottom are a number of types with only one topic, like interview.
Will Moffat mentioned a good idea a while ago: setting goals for adding data within domains and types, and having visual indicators of progress within those domains. Freebase could make some back-of-the-envelope estimations for how many entries are missing in a certain type. This is needed because low number does not necessarily mean missing data (as in days of the week).