I used Dia (http://dia-installer.de/ http://dia-installer.de/) and Lucidchart (https://www.lucidchart.com https://www.lucidchart.com) in the past. It's not idea

I used Dia (http://dia-installer.de/ http://dia-installer.de/) and Lucidchart (https://www.lucidchart.com https://www.lucidchart.com) in the past. It's not ideal but it can do the job.