There are quite a few, but as a recent public one - https://oss.love is built using Netlify Graph. It pulls in data via the GitHub API using Netlify Graph, as an example.
Another simple one would be building a chart of Salesforce opportunities to serve as an office sales gong https://www.youtube.com/watch?v=ZTaETEkZ6hE
We have customers who build a product using Netlify Graph to manage Salesforce leads/opportunities/etc. inside of Slack, etc.