Might come as a surprise to some of you, but tea can contain gluten from additives & cross-contamination, in which barley or malt is added for flavorings. Teavana is known for adding such additives in their tea (and I got glutented from it one time).
Say, I'm interested in some tea. I first need to look up its country of origin, because that tells me about how good the food labeling laws is. If it's from Australia / New Zealand, this means the label will always state gluten. If it's from EU (not pan-Europe) it's also good, except they allow products with < 20 PPM to be labeled gluten-free. But this is still good. If it's from USA, a lot of scrutiny is called because the US FDA does not enforce gluten labeling, only wheat is required. But not all gluten-y stuff is wheat :/
In this case, I'm interested in Turkish tea. So I asked a Turkish friend to do some digging for me on the manufacturer's website, since I couldn't find the info in English. He reported that he didn't find any info about gluten on the website, but he send me a photo of the package where the ingredients are listed. I spotted German on the labels, this is a good sign because it means this product is also sold in Germany, and food labels have to comply with the country it's being sold in too*.
That's pretty much end of story. Ordered the tea and brew it. Tastes very good!
*Thank you a local Thai QA who told me about this 🙏