Telegraf is a lightweight, plugin-driven collection agent written in Go that collects data about systems and applications, allowing users to easily contribute functionality without knowing the codebase. It has over 150 plugins, with most contributed by the community, giving it the ability to collect metrics from various inputs and write them to different outputs. Telegraf's input plugins need to satisfy three interfaces: SampleConfig, Description, and Gather, which are used to generate configuration files using TOML. The Trig plugin is an example of a Telegraf plugin that generates sine and cosine waves for demonstration purposes, demonstrating how to create a new plugin by fulfilling the interfaces and importing it into the main Telegraf package. To contribute a new plugin, users need to write tests, a README.md file, a LICENSE file, and sample input/output formats, and follow the excellent guide on GitHub.