So we used to have these things called personal tags. Basically it was a tag that was tied to your username. ie: #insomniasexx.goodlongread You could see, ignore, follow, etc by both the user and the tag. It seems like it might work for what you are talking about (too bad we ditched it).
The reason for implementing them was to give people the ability to see (and not see) exactly what they wanted—super granular control. The problem was (as seen in the comments of the hubski update post above), they weren't actually being used. Everyone generally agreed that it was a good concept but, for whatever reason, the implementation wasn't good.
We do still have lists. Example:
Basically, you put these together manually by stringing together pub id numbers separated by commas. Obviously though, it's not optimal because it is manual. We never saw much love for them so we never coded up a way to do them easier but if you had any ideas of a sweeter implementation, we're literally all ears.
We also allow some "URL hacking" (aka query strings) as announced here:
So you could generate a "personal tag" still by doing something like this:
Or, for your universe/story example by doing:
We don't have an "or" command do something like "show posts tagged this by this author or that author. It also doesn't seem that stacking tags works (ie: https://hubski.com/tag?id=goodlongread&tag=crimestories)
mk or forwardslash could certainly code those up in a jiffy though, right guys? (don't kill me).