What is the difference between Discovery, Basic, Full scan type?

Full scan

It contains a default vulnerability scan where the Default vulnerability categories test is chosen by default, and others are skipped to increase the stability and performance of the scanned hosts.

The Full scan includes the following settings:

Basic scan

It allows you to create your custom selection of vulnerability tests.

The Basic scan includes the following settings:

Discovery scan

This will limit the scan to only identifying what assets are considered to be alive.
Selecting this scan in the profile will limit the scan profile to only Host discovery and Port coverage.

The Discovery scan includes the following settings: