Hello Jawad,
Metrics are to be chosen from a drop-down list in Stackdriver. The usual interest is to get notified if the value of the metric crosses a certain chosen threshold. There is also an alert for missing metrics, but not for present metrics. This is very likely due to the fact that a present metric has a value. If you set it to zero (or a very small number, for that matter), then you get notified if a metric is present.
To further clarify your requirement: what do you mean exactly by a present metric and how do you imagine the most interesting use case for that situation, step by step?