SAP Transaction Codes useful for ABAP Development.

Tcode	Description
AL11	SAP Directories
BAPI	BAPI Explorer
CMOD	Project Management of SAP Enhancements
OAOR	Business Document Navigator
SA38	ABAP : Execute Program
SALE	IDoc and ALE Development
SCDO	Change Document Objects
SCI	Code Inspector
SCOT	SAPConnect : Administration
SE01	Transport Organizer (extended view)
SE03	Transport Organizer Tools
SE09	Transport Organizer
SE11	ABAP Dictionary
SE14	Database Utility
SE16	Data Browser
SE18	Business Add-ins(BADI’s): Definition
SE19	Business Add-ins(BADI’s): Implementation
SE24	Class Builder
SE30	ABAP Runtime Analysis
SE36	Logical Database Builder
SE37	Function Builder
SE38	ABAP Editor
SE39	ABAP Splitscreen Editor
SE41	Menu Painter
SE43N	Area Menus
SE51	Screen Painter
SE71	Form painter
SE75	SAPScript Settings
SE80	Object Navigator
SE91	Message Maintenance
SE93	Maintain Transaction
SHD0	Transaction & Screen Variants
SHDB	Transaction Recorder
SLIN	ABAP program extended syntax check
SM04	User List
SM12	Lock Entries
SM13	Update Requests
SM30	Maintain Table Views
SM35	Batch Input : Session Overview
SM36	Define Background Job
SM37	Simple Job Selection
SM49	External Operating System Commands
SM50	Process Overview
SM59	RFC Destinations
SMARTFORMS	SAP Smart Forms
SMARTSTYLES	Smart Styles
SMOD	SAP Enhancements
SNOTE	SAP Note Assistant
SO10	Standard Text
SP01	Spool List
SPAD	Spool Administration
SPRO	SAP Customizing
SQ01	SAP Query
ST05	SQL Trace
STMS	Transport Management System
ST22	Dump Analysis
SU21	Authorization Objects
SU01	User Maintenance
SU53	Display Authorization Data