Some useful table names for Basis:

TSTCT
List of Transaction Codes

TBTCT, TBTCO, TBTCP
Background Jobs data is stored in these tables

USR02
Logon data

USR04
User master authorization (one row per user)

UST04
User profiles (multiple rows per user)

USR10
Authorization profiles (i.e. SAP_ALL)

USR11
Text for authorization profiles

USR12
Authorization values

USR40
Table with list of password restrictions and prohibitions

AGR_USERS
List of roles assigned to Users

AGR_T-Codes
List of all T-Codes assigned to Users

E070, E070A, E070AS, E071
Transport data is stored within these tables

TST01
Table for TemSe

PAT01
Table for Support packages and updates

PAT03
Status of Support packages and updates

T000
List of all the Clients

SNAP
ABAP dumps are stored here

TPFYPROPTY
Table with list of all dynamically switchable parameter

 

Some Useful Basis T-codes

SU01 - User maintainance

SU3 - Logged in User maintainance

SU10 - Mass user maintainace

SM04 - Shows list of logged in users with T-codes executed on a server

AL08 - Shows list of logged in users globally in all the instances which are active

SM02 - To send system messages

SM36 - To create Background jobs

SM37 - To monitor Background jobs

SMX - To view the status of Background jobs

RZ04 - To create Operation Modes

RZ03 - To switch Operation Modes

SM63 - To define Time table for Operation Modes

SM21 - System log. Log for all the transactions are captured here

SM22 - To view ABAP run-time errors

PFCG - Roles and Profile Maintainance

STMS - To configure Transport Management System

STMS_IMPORT - To import a Transport request

SM59 - To create RFC's

SM58 - To create transactional RFC

SM21 - To create Queued RFC

RZ10 - To create/edit any paramenter

RZ11 - To view individual parameter by name

SA38 - To view list of all the parameters

SE38 - ABAP editor screen

SE16 - To view table entries

SE93 - To create/edit any T-Code

SCC4 - To create Client

SCCL - Local Client Copy

SCC7 - Client Import

SCC8 - Client Export

SCC9 - Remote Client Copy

SCC5 - To delete a Client

SCC3 - To view Client copy logs

PFUD - Mass User comparison

SU56 - To display user context data

SU53 - To display user authorization data

SUIM - To view user change history

ST01 - System trace

ST02 - Memory tune summary

ST03 - Workload Monitor

ST05 - Performance analysis

ST06 - Operating System Monitoring

ST22 - Workprocesses Trace, Message Service Trace and Dispatcher Trace

SE06 - To view system change options

SE11 - ABAP dictionary

SE80 - Object Navigator

SCOT - To configure SMTP

SOST - To monitor External send messages

SBWP - Business Workplace

SPAM - Support Packages Manager

SAINT - To install add-ons or plugins

SM50 - Workprocesses overview

SM51 - List of SAP Servers

SPAD - To add a printer

SP01 - Spool requests are displayed

SP02 - Output requests are displayed

SM12 - To check lock entries

SM13 - To view update requests

SM28 - To check for any errors after install

SICK - To check for any errors after install

SLICENSE - To install a permanent license

SNAP - ABAP dumps are stored

SE01 - To create a transport request

SE09 - To create a change request

SE10 - To create a change request

RZ70 - To connect ABAP to SLD

RZ20 - CCMS Monitoring

RZ21 - CCMS Remote Monitoring

SGEN - Load Generator

SMSY - To generate Solution Manager Key

What is a Transaction Code ?

Transaction Code: 
   
                    It is a short cut Key attached to a screen. Instead of accessing a screen through SAP Easy Access menu we can navigate to particular screen by entering Transaction Code in Context field.