What is the most used piece of software(s) on your moderm opperating system that is used for your retro systems?

For myself it is hands down "DirMaster" for the Commodore 8-Bits! I am always opening Commodore .d64 .d81 files to see whats in them or to reorganize what files are on various .d64 images.

2nd most used would have to be ADTPro for my Apple // systems. So I can make real floppies from image files of archived software.

3rd is CG Term for dialing into Commodore BBS' from my desktop.

4th VICE, yes this in 4th place if you don't count the VM's running it for test bed and The Kats Alley BBS.

So what are yours??