Some useful TCodes for SAP

1) SU01 User Maintainence
2) SCC4 Client Overview ( Create , Quick Delete , Modify )
3) SCC5 Deletes a client completely with tables & other factors
4) SCCL Local Client Copy
5) SCC9 Remote Client Copy
6) SCC3 Client Copy log Analysis
7) DB02 Storage Management & Database Performance
8) DB12 SAP Backup Logs
9) DB13 Database jobs calender
9) DB14 Database Monitor
10) SM12 Lock Entries
11) SM21 System Logs
12) SM36 Background Job Scheduling
13) SM37 Background Job Monitoring
14) SM31 Table Maintenance
15) SM50 Process Overview
16) ST22 ABAP Dumps
17) ST02 Buffer Analysis
18) ST03 Workflow Analysis
19) RZ04 Operation Mode
20) SE09 Transport Organizer
21) SCC1 Copy as per Transport Request
22) STMS Transport Management System