Finding backgrounds for indoor portraiture can be a pain after a while. You can get mileage out of proper backdrops and different lighting setups, but there's an option for punchy portraits with for all intents and purposes, unlimited variations.
For years I have been using my Samsung tablet as a backdrop for commercial macro images. It has been a staple of how I work for a while and I've used it in a number of ways. For some reason, however, I've not once made the connection of using a television for bigger subjects. In this video Joe Edelman, the happiest photography educator I've ever seen, goes through some shots he's created using an LED television as a backdrop and they are stunning.
There are a few caveats to this method I would say: firstly, you need a large LED TV which if you don't already have one, is quite the expense (albeit one that has other justifications to go along with it.) Secondly, you need to know how to light properly to avoid an odd, mismatched portrait. Creating cohesion between the brightness of the background and the foreground is paramount to success. With a bit of trial and error, however, you have access to so many creative images you will essentially never run out.