SAP tables regroups the most used tables in SAP. the main Tables in SAP are classified by module.
You will find a PDF for the list of SAP Tables. 

SAP Tables for Production Planning PP

• PRODUCTION PLANNING (PP)
  • WORK CENTER
  • ROUTING/OPERATIONS
  • BILL OF MATERIAL
  • PRODUCTION ORDERS
    • Tables diagram for production orders
  • PRT’S PRODUCTION ORDERS
  • PLANNED ORDERS
  • KANBAN
  • RESERVATIONS
  • CAPACITY PLANNING
  • PLANNED INDEPENDENT REQUIREMENTS
  • ORDER’S STATUS
  • ORDER’S STATUS CHECK
    • FUNCTION ‘STATUS_TEXT_EDIT’
    • CALL FUNCTION ‘STATUS_READ’
    • FUNCTION STATUS_NUMBER_CONVERSION

More about SAP PP Main Tables

SAP Tables for Material Management (MM)

• MATERIAL MANAGEMENT (MM)
  • MATERIAL DOCUMENT
  • PURCHASING

More about SAP Material Master Tables

SAP Tables for Production Maintenance PM

• PLANT MAINTENANCE (PM)

SAP Tables for Production Planning PS

• PROJECT SYSTEM (PS)
  • BASIC DATA
  • EQUIPMENT

SAP Tables for Quality Management QM

• QUALITY MANAGEMENT (QM)
  • INSPECTION LOT / INFO RECORD
  • QUALITY NOTIFICATION
  • CERTIFICATE PROFILE

Find the list of the most Important SAP QM Tables (Quality Management)

Tables for SAP Master Data

• MASTER DATA
• MATERIAL MASTER
  • Basic data text (sap script)
  • Batches
• CUSTOMER MASTER DATA
• VENDOR
• CUSTOMER – MATERIAL INFO RECORD
• BANK DATA

See also SAP Material Master Tables and SAP KNVV: Customer Master Sales Data

SAP Tables for Customizing

• CUSTOMIZING
  • GENERAL SETTINGS
    • Countries
    • Currency
    • Unit of measure
    • Calendar functions
  • ENTERPRISE STRUCTURE
    • Definition
    • Assignment
• FINANCIAL ACCOUNTING
  • Company code
  • Fi document

Tables for Characteristics in SAP

• CHARACTERISTICS
  • CHARACTERISTICS
  • CLASS TYPES AND OBJECTS
  • LINKS

To learn more about characteristics in SAP, check SAP Classification / Characteristic Overview and Tables (AUSP)

 Tables for BC ( Basic and Administration ) in SAP

• BASIC DATA / ADMINISTRATION
  • WORKBENCH RELATED TABLES
    • Data dictionary tables
    • Workbench
  • ADMINISTRATION
    • User administration
    • Batch input queue
    • Job processing
    • Spool
    • Run-time errors
    • Message control
    • SAP EDI transactions: List of EDI Codes
    • Change documents
    • Reporting tree table
  • SETTINGS
  • MASTER DATA
  • INFOTYPES

SAP Tables for Finance and Controlling ( FI/CO)

• FI/CO
  • FI
    • Master data
    • Accounting documents / indices
    • Payment run
  • CO
    • Cost center master data
    • Cost center accounting

Tables for Sales and Distribution (SD) in SAP

• SALES AND DISTRIBUTION (SD)
  • SALES ORDER
  • BILLING DOCUMENT
  • SHIPPING
  • DELIVERY
  • PRICING
  • CONTRACTS

Tables for Warehouse Management (WM) in SAP

• WAREHOUSE MANAGEMENT (WM)
  • TRANSFER REQUIREMENT
  • TRANSFER ORDER
  • MASTER DATA – STOCK POSITIONS
  • INVENTORY DOCUMENTS IN WM

find the list SAP WM Main Tables by Topics

PDF file grouping Main Tables in SAP

All the tables are grouped in the following PDF