I am thinking of a tag for questions about 'how many...', where the answer is (in part) an objective number.
- How many unique on'yomi are there?
- Which kanji has the greatest number of strokes?
- Statistics of on-yomi phonemes/syllables
- If you learn the 2000 most common kanji, how many of the 2000 most common hanzi would you know?
Exact name open to discussion: 'statistics', 'quantitative', 'frequencies', etc.