Sure, Lucid Lucidchart is awesome.

But have you considered these open source alternatives?

They are free, self-hostable and community-driven.

Check by yourself: Excalidraw  Excalidraw , diagrams.net  Draw.io , Mermaid  Mermaid Live Editor .

  1. So is Excalidraw Excalidraw

    Whiteboard for sketching hand-drawn like diagrams

    ★ 88.3k diagram whiteboard License: MIT

    An open source virtual hand-drawn style whiteboard. Collaborative and end-to-end encrypted.

    preview

  2. So is diagrams.net Draw.io

    JavaScript, client-side editor for general diagramming

    ★ 51.8k diagram License: Apache-2.0

    Browser-based diagramming components and applications.

    preview

  3. So is Mermaid Mermaid Live Editor

    Edit, preview and share mermaid charts/diagrams

    ★ 4.4k diagram License: MIT

    Edit, preview and share mermaid charts/diagrams.

    preview