This subgraph indexes and exposes in GraphQL all the event data related to the GovernorAlpha and CompoundToken contracts from Compound, providing an easy access to Token holder and Delegates information, Proposals and votes casted, and all the relationships between those entities.
A live version of this subgraph can be found here, along with useful queries and examples already available on the playground.
We don't keep track of historical data via entities, since as of the v0.17 GraphNode update they implemented "time-travel" queries, which allow to access the subgraph state for any block number, which allows to get any historical data that you might need from subgraphs, and also calculate with any granularity the data changes that happen on the subgraph.
We recommend this article from the Blocklytics team, which explains how to take advantage of "time-travel" queries and also how to translate timestamps to block numbers, which might be better suited for some use cases!