We have a tag called arrowverse for the shared universe between Arrow, The Flash, DC's Legends of Tomorrow, Vixen, and Constantine. When questions are about more than one show, it certainly makes sense to tag it with that:
- Where does Vixen S02E01 fall in Arrowverse timeline?
- Do "Arrow" and "The Flash" share sets?
- Is Gideon on The Flash and Gideon on Legends of Tomorrow same?
However, there are a number of questions that have been tagged with this, but they only have to do with one show. In most cases, the original poster didn't use the tag, but it was edited in later by another user:
- Why was the "Green" removed from "Green Arrow"?
- What happened to the child Barry Allen in The Flash S3 Premiere?
- Why did Vandal call him by that name and what does it mean or reference?