I created a short AZ-900 cheat sheet while studying, and it turned into a very useful way to organize the fundamentals.
For me, the most helpful part was turning the concepts into simple mental models and quick comparisons:
- IaaS / PaaS / SaaS.
- CapEx vs OpEx.
- Azure Policy vs Blueprints.
- Azure Monitor vs Service Health.
- VM basics, Bastion, storage redundancy, and RBAC.
The goal was not to create a giant study dump, but a short, practical cheat sheet that is easy to scan and remember.
Link: AZ-900 cheat sheet