Gaming is saturated, but good. It has a lot of sub-niches. For example:
Gaming
-Game engines
-Gaming companies
-Game series
-Console or PC
Those are just off the top of my head. All you have to do is make your tag marketable.
Gaming was just an example. Maybe I should have worded it better.
What I want to know is are you better going for a big niche like "gaming" OR find less saturated niches like your examples for instance.
Personally, I go for saturated niches with a good amount of sub-niches. If I am not as successful in the big niche as I want to be, then I am still targeting 10+ sub-niches, and I still get the followers and retweets from the users who follow the "official" bigger niche accounts. On top of that, your sub-niches often have a sub-niche. So, why not go for the big fish and catch the little ones along the way?