What are the Japanese terms for “reaction” or “let’s play”, as seen on the English side of YouTube

So I passed N3 and am preparing for N2 and thought an entertaining way to pass the time might be to watch some more YouTube from native speakers.

In particular I'd like to watch someone play a game or watch a movie/show I've already seen because that will allow me to use context to help a lot in understanding what's going on if they use some words I'm not familiar with.

Just have no clue what to search for to find this kind of thing. Is it literally called リアクション? Is there a more native/ nuanced term that will provide better results?

Thanks