.7z seems to be good and I do recommend it to people, saying that it's better than regular zip. Have recently started using opus n webm files more.

I've also heard about jxl recently. Would be very nice to see it become popular, as it could reduce the size of my memes n screenshots folders. Faster webpage loading too.

Are there any other file formats that'll be useful to people, but isn't getting enough attention?

In the case of apps, Trebleshot seems to be good for android file sharing. I like it's web sharing option having an upload form. Helps me where I don't have to ask others to install an app to send me a file locally. Not sure about its encryption n security aspects, but I only have used it for local file sharing.

And what about other stuff similar to that, other than file formats or apps?

Recently have started exercising my neck. Not neck bridges and loaded things tho. Only safe n simple movements. Seems to be good, especially after using a monitor for some time. I think it's not much talked about, maybe because of the fear that people will overdo it?