I often get asked what I use or prefer to use for putting together diagrams. It really all depends on the goal
Draw.IO
Link: htp://draw.io
For Diagramming (Cloud Architecture, Flowstate, Data-Flow Diagrams) I prefer to use Draw.IO In many cases fills the need of full-blown Vizio with out the need to have office 365 or heavy bloat where on your systems.

- Pros
- Free without limits
- Flexible with tons of templates
- Exportable
- Cons
- Export to other formats have to to be tinkered with
(Specifically exporting the visio format it never comes out right)- I most causes using windows screen clip (win-key + s) is a reasonable compromise
- Export to other formats have to to be tinkered with
Quick Database Diagrams (QuickDBD)
Link: https://app.quickdatabasediagrams.com/#/
I was looking for a few database diagraming tools to visualize a database schema I was putting together . A nice ERD web based interfaces that will allow you to import your database schema to create a beautiful diagram.

- Pros
- QDD is currently providing an unlimited version if you post about the using tool (which I’m still waiting to receive).
- For the limited free version I have it cuts everything I need
- Cons
- Free but with some limitations (up to twenty objects)
- Lack of modern databases mongo, postgres, and NoSQL sql databases to import and export from would be my biggest detractor
ARMViz
Link: http://armviz.io/designer
ARMViz provides the ability to create diagrams from your Infrastructure as Code/ARM templates for Azure. The interface allows you to create new resources as well and export it to an arm template that you can deploy.
You can also use a set of predefined to templates to work from visually like below and enhance as needed for your diagram or deployment efforts.

Others?
I am curious know what other apps/tools in the community use for diagramming and charting that are free. Feel free to comment or chime on this post or email if you have any thoughts.