We've tried Github's wiki and checking it into source control but I've found that Google Sheets was the best option because it allowed our non-technical stakeholders to also provide feedback on our test data. We have also been able to leverage the Google Sheets API for our data-driven testing.
What tools does your company use to share testing data?
Google Sheets is one option, but there are many others!
The tools that Stacy suggested will certainly work for you.
Is your team using JIRA? There are a few different add-ons that Atlassian offers that can help your team share data more easily and increase visibility into project status. I find that this list may be helpful to you: http://getzephyr.com/insights/using-marketplace-add-ons-get-most-out-you....