[neutralx]

First image in the article reminds me of draw.io diagrams. Is this a drawio theme/library or some other tool was used to create it?

[philipwhiuk]

https://excalidraw.com/ probably

[neutralx]

Yep that looks like it. I also found that drawio indeed supports sketch theme: sketch.diagrams.net

[croisillon]

the font seems to be Excalifont indeed