I don't want to be that shameless, but https://onthesamepage.online https://onthesamepage.online does just that. I use it for sketching diagrams and mind maps d

I don't want to be that shameless, but https://onthesamepage.online https://onthesamepage.online does just that. I use it for sketching diagrams and mind maps daily. Not for presentations, but can export to PNG and SVG. Also kind of collaborative (I often use it alone, but from both tablet and laptop at the same time).