PGF and TikZ is described as 'PGF/TikZ is a tandem of languages for producing vector graphics from a geometric/algebraic description. PGF is a lower-level language, while TikZ is a set of higher-level macros that use PGF' and is an app in the Photos & Graphics category. There are more than 10 alternatives to PGF and TikZ for a variety of platforms, including Mac, Windows, Linux, Online / Web-based and PortableApps.com. The best alternative is Inkscape, which is both free and Open Source. Other great apps like PGF and TikZ are LibreOffice - Draw (Free, Open Source), Dia (Free, Open Source), Lucidchart (Freemium) and Graphviz (Free, Open Source).
Asymptote is a powerful descriptive vector graphics language that provides a natural coordinate-based framework for technical drawing. Labels and equations are typeset with LaTeX, for high-quality PostScript output.
LaTeXDraw is a graphical drawing editor for LaTeX. LaTeXDraw can be used to 1) generate PSTricks code; 2) directly create PDF or PS pictures. LaTeXDraw is developed in Java and thus runs on top of Linux, Windows, and Mac OS X.
Ludigraphix is a geometry oriented vector drawing software where shapes are defined by points that can be shared with other shapes. This allow you to build complex shapes that can be manipulated in a lot of different ways.