Useful T-codes For SAP BI

Used ECC side
RSA2	Used to display all the details of a DataSource
RSA3	This is Extractor Checker, we can check the data of any
	DataSource at ECC side using this tcode.
RSA5	This tcode is used to activate the Standard DataSources
RSA6	By using this tcode we can see all the activated Data Sources
	and also we can enhance the DataSource by adding new fields
RSA7	Used to display the delta Queues
RSO2	Used to create and display the Custom DataSources
LBWE	Customize LO Datasources
LBWQ	Used to manage the logistic Delta queues.
LBWG	Used to delete the logistic setup tables.
SBIW	BIW in IMG for OLTP
SMQ1	Used to check the queued data for delta
SM37	Used to monitor the Background jobs
SE38	Used to Create, edit and Display the ABAP programs
SE16	Used to see the data of database tables
SE11	Used to create and display Structures, Views and Tables
SM58	Used to Manage the Transactional RFCs
SE37	Used to create and display Function Modules.
SE80	Object Navigator
SE10	Transport Organizer
CMOD	Project management of SAP enhancements
SMOD	SAP enhancements for a Datasource
ST05	Performance Analysis
Used BI Side
RSA1	Data Warehousing Workbench Modeling
RSKC	Used to maintenance of the permitted extra characters in BW
RSBBS	Maintaining BW SenderReceiver
RSPC	Used to create or monitor the Process Chains
RSPC1	Used to Maintain Process Chain(One Chain)
RSZC	Use to copy the query from one InfoProvider to other InfoProvider
RSPCM	Used to monitor the Process Chains
RSRT2	Start of the Report Monitor
RSANWB	Analysis Process Designer
RSPLAN	Modeling BI Integrated Planning
RSCUR	StartCurrency Translation Type
RSMO	Data Load Monitor Start
RSRV	Analysis and Repair of BW Objects
RSSM	Authorizations for Reporting
RSSMQ	Start Query with User
BD87	Used for idoc
SBIW	BIW in IMG for OLTP
LISTCUBE	Used to display the content of InfoProvider
SE10	Transport Organizer
CMOD	Project management of SAP enhancements
SMOD	SAP enhancements for a customer exit variables
SE11	Used to create and display Structures, Views and Tables
SM12	Unlock the locked Objects
SM59	Configuration or RFC connections
SM37	Used to monitor the Background jobs
DB02	Database performanceTables & Indexes
ST22	Used to check the ABAP run time error
AL11	Used to Create or Display SAP Directories
FILE	Change view “Logical file path Definition” Overview
RSSMTRACE	Reporting Log Authorization
RSECADMIN	Used to maintain the BISecurity
RSZDELETE	Used to Deletion of query objects
RSBBS_WEB	Transaction for the RRI in the Web

Note: The above mention T-codes are most commonly used t-codes if you want to search more t-code you may use t-code SE93.