Choosing nodes in Azure AKS
You cannot use the A-Series or B-Series but otherwise there is free choice.
The D-Series suit most setups but you can also choose other series if you weigh cores/memory needs differently.
The F-Series, H-Series, and N-Series work fine, but you pay for something that is not needed, for example GPU, HPC, and so on.
There are savings in looking at cost reservations over several years.