Back in the day, I did a lot of reverse engineering of code (not so much these days). Back then (and I supposed still is), Hexrays IDA was the king of the hill. Pricey though for a legal copy.
I also had a license to SoftICE through my work back in the DOS/Win3.1 days (complete with a homemade NMI switch wired into an ISA slot). I'm not sure they still make SoftICE though. I also used wdasm and ollydbg a few times.
I've heard a lot about Ghidra in the past few years, and it seems to be taking over even from pirated IDA copies. If/when I have another RE opportunity I intend to look at it, since I no longer have any of the aforementioned tools handy, or even if they're still usable/supported/maintained on modern OS/CPU architectures.