This document provides a list of 120 transaction codes for SAP modules like Basis, ABAP, MM and SD. A transaction code is a 4-character code that guides users to a specific screen in SAP to perform a task. The list includes transaction codes for functions like example library, keyword documentation, operating system alerts, database performance, transport organizer, data dictionary maintenance, ABAP editor, and more. Transaction codes are stored in the SAP table TSTCT along with their corresponding texts.