Mandeep Gulati, there are several alternatives to create graphical abstracts such as Cytospace, Gimp, ImageMagick, ImaheJ, Inkspace, and R. Some of these are basic and simple to use while others have more drawing tools and require more effort. Gimp and Inkscape, for example, are two good open-source, semi-professional programs. Choosing one that will work for you will depend on your needs. You can find information, URLs, and tips on https://www.enago.com/academy/which-tools-should-you-use-to-design-quality-images-for-research-papers/.

I hope this helps!

I don't know what type of figures you have in mind. Probably you can try https://app.diagrams.net/

Hola Mandeep Gulati

El gráfico enviado por Christopher Busuttil es un excelente resumen de las alternativas gratuitas.

Si lo que quieres es encontrar un versión gratuita de Power Point te sugiero Slides de Google. Este es un SaaS que incluso permite trabajar colaborativamente. Y sirve para hacer presentaciones.

Con relación a Publisher te sugiero Libre Office (publicación con varias páginas) o Google Drawings que incluso se trabaja como Slides de Google (para infografías o gráficos).

Espero que te sirva toda la info que te sugiero.

Saludos cordiales

Use Inkscape. Inkscape is a Free and open-source vector graphics editor for GNU/Linux, Windows and macOS X. It offers a rich set of features and is widely used for both artistic and technical illustrations such as cartoons, clip art, logos, typography, diagramming and flowcharting