Metrics

In Dynatrace, you have various types of metrics at your disposal:

Built-in metrics provided by OneAgent. These have the builtin: prefix in the metric key.
Extension metrics provided by OneAgent or ActiveGate extensions. These have the ext: prefix in the metric key.
Calculated metrics you create. These have the calc: prefix in the metric key.
Custom metrics you can feed to Dynatrace via metric ingestion. These don't have any fixed prefix, as the ingestion protocol is completely flexible.

Infrastructure metrics and other periodic metrics are captured every 10 seconds and stored as 1-minute aggregates. Typically, this includes a min/max/count/sum/average of the measured metric.
Service and web request metrics do not have a frequency. Dynatrace captures the transactions and displays medians and 90th percentiles. RUM and service analysis pages are based on this data.
For custom metrics ingestion, the standard resolution is 1 minute, but you can also get statistic summaries.