Apple IIGS Software Development Tools from the Skunk Works BBS Archive:

FOUNDATN102.SHK Foundation v1.0.2, the first freeware release of this resource creator/editor
GIFVIEW.SRC.SHK source code to GIFview (a GIF viewer for the Apple IIGS)
MODEMMAN12.SHK  Routines to make writing comm software easier
PIXIE240.SHK    Memory debugger CDA
SUPERMAGIC3.SHK Set of animation routines for use in your own programs
TOOLTRACE.SHK   Tool Tracer, a CDA which flashes the border when a particular tool is called
XLISP21E.SHK    XLISP-PLUS 2.1e, a Lisp interpreter quite close to Common Lisp.  Docs are included.  Needs at least 500kB free RAM and a shell program like GNO/ME or ORCA.