The Beats are lightweight data shippers that you install your server to send different types of operational data to Elasticsearch.
Filebeat, Metricbeat and Packetbeat are a few examples of Beats.
In more detail, filebeat is used for retrieving logs from your servers.
Where as Packetbeat is for monitoring the network traffic exchanged between your servers.
Metricbeat periodically collects metrics from the operating system and from services running on the server.
We can look metricbeat more closely.
Metricbeat could help monitor servers by collecting metrics from systems and services.
Metricbeat consists of modules and metricsets. A Metricbeat module defines the basic logic for collecting data from a specific service, such as Redis, MySQL, and so on.
The module specifies details about the service, including how to connect, how often to collect metrics, and which metrics to collect.
Also, metricbeat can send data directly to Elasticsearch or send it to Elasticsearch via Logstash, which you can use to parse and transform the data.
There are already 25+ Community Beats made by the community. Community Beats keeps growing for every day.