Default Programs Editor - Default Programs Editor is a powerful but simple file association utility for Windows 7, Vista and...
RCDefaultApp - RCDefaultApp is a Mac OS X 10.
FileMenu Tools - FileMenu Tools lets you customize the context (right-click) menu of Windows Explorer.
Easy Context Menu - Easy Context menu is a Freeware portable utility that includes useful tweaks for the context menus.
Duti - duti is a command-line utility capable of setting default applications for various document types on macOS, using Apple's Uniform Type Identifiers (UTI). It's the CLI analog to RCDefaultApps and SwiftDefaultApps
Shell context menu manager - Powerful and lightweight context menu manager for Windows File Explorer.