Top TikZiT Alternative Software for Diagramming
TikZiT is a super simple GUI editor designed for creating graphs and string diagrams. Its native file format, a subset of PGF/TikZ, allows for direct inclusion of diagrams in LaTeX-typeset papers. While powerful for its specific niche, users often seek a TikZiT alternative for broader diagramming needs, diverse platform support, or more extensive feature sets. If you're looking to expand beyond TikZiT's specialized capabilities, explore these excellent alternatives.
Best TikZiT Alternatives
Whether you need a versatile flowchart maker, a robust vector graphics editor, or a comprehensive diagramming solution, there's a TikZiT alternative perfectly suited for your workflow. Here's a curated list of top contenders:

Lucidchart
Lucidchart is an online diagram and flowchart software that stands out as a strong TikZiT alternative, especially for those needing Microsoft Office Visio import capabilities and cross-platform compatibility. Available as a freemium web-based tool with Android, iPhone, and Chrome OS apps, it offers real-time collaboration, charts, flowcharts, UI design, prototyping, and export to PDF. Its web-based nature and comprehensive features make it a versatile choice for teams.

Inkscape
Inkscape is a professional, free, and open-source vector graphics editor available for Linux, Windows, and macOS, making it an excellent general-purpose TikZiT alternative for vector drawing. It supports layers, SVG editing, vectorizing raster images, cross-platform use, and live path effects. Its robust features for graphic design and SVG support make it a powerful tool beyond simple diagrams.

LibreOffice - Draw
LibreOffice - Draw is a powerful, free, and open-source vector graphics editor for office use, available on Mac, Windows, Linux, and BSD. It’s an ideal TikZiT alternative for creating charts, diagrams, and brochures. Key features include sequence diagrams, drawing tools, portability, and export to PDF, making it a comprehensive solution for various visual communication needs.

Dia
Dia is a free and open-source GTK+ based diagram creation program available for Linux, Unix, Mac OS X, and Windows. Roughly inspired by commercial Windows applications, it serves as a lightweight TikZiT alternative specifically for creating diagrams. Its features include support for various diagrams, extensibility via plugins, flowcharts, and WYSIWYG support, making it a straightforward choice for quick diagramming.

Lucidchart
Lucidchart is an online diagram and flowchart software that supports Microsoft Visio import and works on any operating system. As a freemium web-based TikZiT alternative, it offers extensive features like real-time collaboration, team collaboration, charts, flowcharts, UI design, prototyping, export to PDF, and UML diagrams. Its strong emphasis on collaboration and web accessibility makes it a powerful option for professional environments.

Graphviz
Graphviz is open-source graph visualization software available for Mac, Windows, Linux, and Web. It features several main graph layout programs, along with web and interactive graphical interfaces. For users deeply focused on graph editing and visualization, Graphviz serves as a powerful, free, and open-source TikZiT alternative, especially when dealing with complex data relationships.

Apache OpenOffice Draw
Apache OpenOffice Draw, part of the Apache OpenOffice suite, is a free and open-source graphics editor available on Mac, Windows, and Linux. It provides tools to communicate with visuals and diagrams, making it a viable TikZiT alternative for general-purpose vector drawing and desktop publishing within an office suite environment.

diagrams
Diagrams is a free and open-source powerful, flexible, declarative domain-specific language for creating vector graphics, using the Haskell programming language. Available for Mac, Windows, and Linux, it's a unique TikZiT alternative for those who prefer programmatic diagram generation, offering a high degree of control and precision for technical drawings.

PGF and TikZ
PGF/TikZ is a free and open-source tandem of languages for producing vector graphics from a geometric/algebraic description, available for Mac, Windows, and Linux. PGF is a lower-level language, while TikZ is a set of macros built on top. Given that TikZiT files are a subset of PGF/TikZ, this is the fundamental TikZiT alternative for users who want to work directly with the underlying LaTeX-based graphics language, offering unparalleled control for high-resolution vector graphics.

Asymptote: The Vector Graphics Language
Asymptote is a free and open-source powerful descriptive vector graphics language for Mac, Windows, and Linux, providing a natural coordinate-based framework for technical drawing. It's an excellent TikZiT alternative for users who require highly precise, programmatic control over their diagrams, with integrated LaTeX typesetting for labels and equations.
Each of these TikZiT alternatives offers unique strengths, from cloud-based collaboration to powerful open-source vector editing. Consider your specific needs, such as required features, platform compatibility, and budget, to choose the best fit for your diagramming and graphics creation tasks.