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.
EDIT:
This one’s debatable, but I use it all the time. Plasticity is 3D modelling software that attempts to bridge the gap between practical CAD programs and software meant for 3D artists like Blender. It’s not cheap considering Blender is free, but it’s buy once use forever, and at (I think) $150 it’s within reach of an individual hobbyist who knows what they want and is willing to pay for it.
I paid for a license of obd jscan for my vehicle since it is specific to Dodge/Jeep it can do everything, including activation of features and access to all data in the vehicle. I had to buy a more expensive vlink adapter, but it was only $20 or so. It has saved me tons of money so far. I was able to program keys, activate remote start (had to install a hood switch), and have been able to diagnose several issues with things like tpms and abs.