Reverse Engineering
What I've got open whenever I'm reversing something.
IDA Pro
The standard for disassembling and decompiling binaries. Where most of the real work happens.
dnSpy
.NET decompiler and debugger. Good for editing assemblies
Il2CppDumper
Dumps metadata from IL2CPP builds — gets you real class and method names back.
Process Hacker 2
System monitor and debugger. Handles, threads, memory, DLL injection
Cheat Engine
Memory scanner and editor. First tool most people learn game hacking with.