Reading data across chains

Hello, I'm curious if anybody has come across the situation of being on one contract and needing to read data on another. Say, being on polygon and checking if a user owns an nft on ethereum etc. I've seen a lot of cross chain messengers, but they are generally only for sending transactions/bridging. I'd prefer not to use an api if possible to keep this all decentralized as best I can. Any protocols that you've come across that do this?Thanks for any tips! via /r/ethdev https://ift.tt/C98jeyO