Important transactions Related to ABAP

USMM Pressing F8 will display all hotpacks applied.
SEARCH_SAP_MENU Show the menu path to use to execute a given tcode. You can search by transaction code or menu text.

DI02 ABAP/4 Repository Information System: Tables.
LSMW Legacy System Migration Workbench. An addon available from SAP that can make data converstion a lot easier.
OSS1 SAP Online Service System
OY19 Compare Tables
SM13 Update monitor. Will show update tasks status. Very useful to determine why an update failed.
S001 ABAP Development Workbench
S001 ABAP/4 Development Weorkbench.
S002 System Administration.
SA38 Execute a program.
SCAT Computer Aided Test Tool
SCU0 Compare Tables
SE01 Old Transport & Corrections screen
SE03 Groups together most of the tools that you need for doing transports. In total, more than 20 tools can be reached from this one transaction.
SE09 Workbench Organizer
SE10 New Transport & Correction screen
SE11 ABAP/4 Dictionary Maintenance SE12 ABAP/4 Dictionary Display SE13 Maintain Technical Settings (Tables)
SE12 Dictionary: Initial Screen – enter object name.
SE13 Access tables in ABAP/4 Dictionary.
SE14 Utilities for Dictionary Tables
SE15 ABAP/4 Repository Information System
SE16 Data Browser: Initial Screen.
SE16N Table Browser (the N stands for New, it replaces SE16).
SE17 General Table Display
SE24 Class Builder
SE30 ABAP/4 Runtime Analysis
SE32 ABAP/4 Text Element Maintenance
SE35 ABAP/4 Dialog Modules
SE36 ABAP/4: Logical Databases
SE37 ABAP/4 Function Modules
SE38 ABAP Editor
SE39 Splitscreen Editor: Program Compare
SE41 Menu Painter
SE43 Maintain Area Menu
SE48 Show program call hierarchy. Very useful to see the overall structure of a program.
SE49 Table manipulation. Show what tables are behind a transaction code.
SE51 Screen Painter: Initial Screen.
SE54 Generate View Maintenance Module
SE61 R/3 Documentation
SE62 Industry utilities
SE63 Translation
SE64 Terminology
SE65 R/3 document. short text statistics SE66 R/3 Documentation Statistics (Test!)
SE68 Translation Administration
SE71 SAPscript layout set
SE71 SAPScript Layouts Create/Change
SE72 SAPscript styles
SE73 SAPscript font maintenance (revised)
SE74 SAPscript format conversion
SE75 SAPscript Settings
SE76 SAPscript Translation Layout Sets
SE77 SAPscript Translation Styles
SE80 ABAP/4 Development Workbench
SE81 SAP Application Hierarchy
SE82 Customer Application Hierarchy
SE83 Reuse Library.
SE84 ABAP/4 Repository Information System
SE85 ABAP/4 Dictionary Information System
SE86 ABAP/4 Repository Information System
SE87 Data Modeler Information System
SE88 Development Coordination Info System
SE91 Maintain Messages
SE92 Maintain system log messages
SE93 Maintain Transaction.
SEARCH_SAP_MENU From the SAP Easy Access screen, type it in the command field and you will be able to search the standard SAP menu for transaction codes / keywords. It will return the nodes to follow for you.
SEU Object Browser
SHD0 Transaction variant maintenance
SM04 Overview of Users (cancel/delete sessions)
SM12 Lock table entries (unlock locked tables)
SM21 View the system log, very useful when you get a short dump. Provides much more info than short dump
SM30 Maintain Table Views.
SM31 Table Maintenance
SM32 Table maintenance
SM35 View Batch Input Sessions
SM37 View background jobs
SM50 Process Overview.
SM51 Delete jobs from system (BDC)
SM62 Display/Maintain events in SAP, also use function BP_EVENT_RAISE
SMEN Display the menu path to get to a transaction
SMOD/CMOD Transactions for processing/editing/activating new customer enhancements.
SNRO Object browser for number range maintenance.
SPRO Start SAP IMG (Implementation Guide).
SQ00 ABAP/4 Query: Start Queries
SQ01 ABAP/4 Query: Maintain Queries
SQ02 ABAP/4 Query: Maintain Funct. Areas
SQ03 ABAP/4 Query: Maintain User Groups
SQ07 ABAP/4 Query: Language Comparison
ST05 Trace SQL Database Requests.
ST22 ABAP Dump analysis
SU53 Display Authorization Values for User.
WEDI EDI Menu. IDOC and EDI base.
WE02 Display an IDOC
WE07 IDOC Statistics