There's plenty of text only repo's to contribute to. The first one that had a merged PR was this Hacktoberfest Swag list. I discovered it looking to see if any other companies had incentives for completing PR's. Turns out they do, also, turns out most require a little more work than just updating a couple text documents. :D
The second one I discovered and contributed to appears to have been created simply for folks to complete easy text contributions Hello World in different languages in which I submitted a powershell file.
Day 1 and I'm 50% to getting my t-shirt. How are you doing?