The best free alternative to Lucidchart is diagrams.net, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 100 alternatives to Lucidchart and loads of them is free so hopefully you can find a suitable replacement. Other interesting free alternatives to Lucidchart are Dia (Free, Open Source), yEd Graph Editor (Free), LibreOffice - Draw (Free, Open Source) and Freeplane (Free, Open Source).
UMLet is an open-source UML tool with a simple user interface: draw UML diagrams fast, export diagrams to eps, pdf, jpg, svg, and clipboard, share diagrams using Eclipse, and create new, custom UML elements.
Linked Ideas is an application to assist you in your note taking and "putting your mind" on the canvas. The thought process of people can be quite chaotic we have similar "bits" of ideas and connections between them, with Linked Ideas.
Mockup Designer, built with Backbone, Backbone-LocalStorage and Html2Canvas, is a super-easy-to-use mockup tool that uses the local storage of your browser as its backend. However the data layer is loosely coupled, so you can integrate with any RESTful API or any Backend service.
Nothing to download/install, create and access your mockups from anywhere. Add pages with templates and define links to present a clickable prototype. Our components are of medium-fidelity not very sketchy or look too real. Its just right.
Life is full of decisions, have the answers at your hand. Join the #1 decision making and question solver expert community. iBoske allows anyone to easily create decision trees. It can be used as a troubleshooting tool.
M8! is an easy to use Mind Map Application for Windows 8. You can use M8! for your thoughts, ideas, for taking notes, for your studies or as an organizer for your business tasks. It's an all-inclusive companion that helps you manage your daily life in every situation.
Violet is a UML editor with these benefits: Very easy to learn and use. Draws nice-looking diagrams. Completely free. Cross-platform. Violet is intended for developers, students, teachers, and authors who need to produce simple UML diagrams quickly.