Over the years many variants have been explored:
The simplest such arrangement is the Dyson ring, in which all ‘energy harvesting structures’ share the same orbit.
Add multiple Dyson ring structures and you will get a Dyson swarm.
Such an arrangement would be known as a Dyson Bubble
Then there is the fictionally popular version – The Dyson Shell, where a uniform solid shell of matter just encapsulates the entire star.
And many many more. But you get the gist.
Could there be Dyson Spheres out there?
When scientists were monitoring the brightness from some stars, they
found that it fluctuated in some odd ways like so:
Brightness v/s time for KIC 8462852
It is common for such dips to occur since when a planet eclipses a star, there would a drop in the brightness observed from the star.
Brightness v/s time for a binary star system
But what was inconsistent is the duration and period of occurrence of these dips.
Although the main line of rationale remains as asteroid impact remnants or interstellar collisions causing these aberrations in data.
But to say that these could the signs of an alien civilization does remain to be the more entertaining interpretation.
Great Question. Thanks for asking !
** For more information. check out this TED talk