Counter is a Metric that represents a single numerical value that only ever goes up.

CounterVec is a Collector that bundles a set of Counters that all share the same Desc, but have different values for their variable labels.

Gauge is a Metric that represents a single numerical value that can arbitrarily go up and down.

GaugeVec is a Collector that bundles a set of Gauges that all share the same Desc, but have different values for their variable labels.

A Histogram counts individual observations from an event or sample stream in configurable static buckets (or in dynamic sparse buckets as part of the experimental Native Histograms, see below for more details).

HistogramVec is a Collector that bundles a set of Histograms that all share the same Desc, but have different values for their variable labels.