Things that I know, although in some I am (much) more confident than in others.
ZX Basic, FORTRAN, C, Unix tools, Pascal, COBOL, SQL, LISP, Prolog, FORTH, PostScript, Smalltalk, Tcl, SGML, HTML, JavaScript, XML, CSS, C++, Java, Python, Ruby, Go, APL, Rust, ... (in rough chronological order)
Unix (Linux, Irix, Solaris, BSD, SunOS, HP-UX, System V, etc.), Microsoft Windows, MacOS, DOS, Cisco IOS, JunOS.
RCS, SCCS, svn, hg, git.
vi, vim, troff, TeX, LaTeX, FrameMaker, Microsoft Word, Microsoft Excel, Microsoft PowerPoint, LibreOffice.