Nodes - Historical data about detected full nodes.

Mempool - Historical data on full node mempool size.

Propagation - Comparisons of block and vote propagation times on the network.

PoW - Proof of Work mining pool data.

VSPs - Voting Service Provider data.

Exchanges - Historical exchange rate information.

Community - Historical data points for twitter, reddit, github, etc.

Stats - DB stats about dcrextdata.