Strawberry Software	Has Plugins Pro, Lifeboat and other good utilities.
Ohanaware	App Wrapper to code sign and notarize and many good utilities
Scientific Specialties	Some great books about Xojo and use of Xojo with Raspberry PI and electronics.
Xojo Inc	The makers of Xojo
Xojo Blog	The official Xojo Blog
Buoy	The makers of Buoy,  A cross-platform, compiled programming language and UI framework with a BASIC-like syntax
Objo	Rapid desktop application development for macOS, Windows and Linux using a powerful BASIC-like language.
MBS Plugins	A lot of plugins for Xojo.
MacOSLib	Macoslib A Macintosh library to use advanced features which are not available in Xojo
Thomas Templemann’s page	TT also has the excellent ZIP Archive classes
Valentina	The incredibly fast and powerful database engine.