For me, that would be Secure CRT. I have yet to find a terminal emulator that matches its feature set. If you regularly manage hundreds of machines using various connection protocols (serial and ssh mostly in my case) It’s worth the $$$, and so far there hasn’t been any subscription nonsense. I liked using it at work so much I forked over the dough to have it at home.
None of the free alternatives do everything I need.
I’ll also mention a few iOS apps. One is Sun Surveyor. It’s an AR app that shows you the position of the sun, moon, and galactic center at any given time. The other would have to be Radarscope. It’s a weather radar app, but it’s a really good weather radar app.
Symphonium, a music app for android (maybe also iOS, dunno). I’ve tried so many other apps for both local and remote music, none of them come even close - I particularly like the pre-caching and rolling cache features, as there are some places I go regularly where connection is spotty, and they allow me to stream pretty much uninterrupted from my subsonic server.