This calculator app maybe I use it for nostalgia’s sake but I’ve had it on every android for the past 10+ years. It works great, launches instantly, and the ads were never more than a small banner at the top. I did buy the ad free version but it’s $2, no subscription or any bullshit, just a straight and honest scientific calculator.

Maybe not underrated because everyone should already be using it but KDE connect is a life changing app. So much functionality packed into a lightweight package. Just having a shared clipboard between my phone and laptop has been such a time saver every single day. If you don’t already have it, you should.