[aratno]

Monodraw is one option: https://monodraw.helftone.com/

Whimsical is another: https://whimsical.co/

[markhops]

Monodraw is nice, but I wish it was web based

Whimiscal looks really cool. I really wish it would provide a shareable link to my rendered diagram (jpg or png) that I could embed in my Github readme.