Colorado

by the Legislative Counsel of the CO General Assembly. It provides basic facts pro v con, usually emphasizing fiscal data only where it exists. But, it is a great place to start and I've relied on this for years--always comes in the mailbox a couple of weeks before the ballot and the same is available online.

If you google a specific ballot initiative for Oregon that you know is on the ballot, it might direct you to such a site sponsored by a political non-profit or similar.

Or the local and major newspapers. I've had to depend on them in off-year elections to get any sense of these people running for school board and the like--to make sure they aren't anti-vaxxers or MAGAT types. Yet another reason to support local newspapers, given that they are just about the only source for information on the candidates beyond their own campaigns.