Very handy. Many options, blocks, and styles. Link associations remain between blocks when moved around.
A lot of similar tools exist online now, but VERY few with no registration at all.
The result can be saved or downloaded as xml, png or svg directly to your GoogleDrive, OneDrive or Dropbox (is all of this safe?), or downloaded locally
Privacy: we have no feedback of potential problem with this tool and author. But like many online services, you are here providing them with your own data. Depending of the criticity of your data, this is your responsibility to assess author's reputation and potential misusage, and to check and accept their terms and conditions, or not.
Free, No Download/Install required, No registration
