IcoFX - IcoFX is an all-in-one solution for icon creation, extraction and editing.
Replacicon - Just updated to macOS Big Sur? You may have noticed some of the apps in your Dock look a bit inconsistent with the rest of the system.
IconsExtract - Extract icons and cursors stored in EXE, DLL, OCX, CPL files
LiteIcon - LiteIcon is a simple app which allows you to change your system icons quickly and easily.
IconLover - Icon editor for Windows.
Pictogram - Customize macOS app icons with ease