Sure, Miro is awesome.

But have you considered these open source alternatives?

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

Check by yourself: Excalidraw , D2 , Affine , tldraw , Draw.io , Scrumlr .

So is Excalidraw

Quadro branco para desenhar diagramas com aparência de feitos à mão
★ 130K Diagram Whiteboard License: MIT
Um quadro branco virtual de estilo desenhado à mão em código aberto. Colaborativo e criptografado ponta a ponta.

Read more about Excalidraw
So is D2

Turn text into diagrams
★ 25K Diagram License: MPL-2.0
A modern diagram scripting language that turns text to diagrams.

Read more about D2
So is Affine

Espaço colaborativo para sua base de conhecimento
★ 71.8K Knowledge base Note-taking Collaboration Whiteboard License: MIT
Esta é a Edição Comunitária do Affine.

Read more about Affine
So is tldraw

Digital whiteboard with infinite canvas
★ 49.9K Diagram License: MIT
Tldraw is a library for creating infinite canvas experiences in React. It's the software behind the digital whiteboard tldraw.com.

Read more about tldraw
So is Draw.io

JavaScript, client-side editor for general diagramming
★ 62.7K Diagram License: Apache-2.0
Browser-based diagramming components and applications.

Read more about Draw.io
So is Scrumlr

Webapp for collaborative online retrospectives
★ 350 Retrospective Agile Scrum License: MIT
Scrumlr is an online collaboration tool that helps teams reach new heights. Start your first retrospective or collaborative session in an instant - no registration required and completely free and open source.

Read more about Scrumlr