Here is a partial list of Major Components Categories List.
The list doesn't include the sub categories at this stage.
Please check again for more updated categories.

AC-DC Converters
Actuators
Antennas
ASIC
Assemblies
Audio Devices
Automotive Parts
Batteries
Blowers
Cable Assemblies
Cable Management Accessories
Cables
Capacitor Hardware
Capacitors
CBI Circuit Board Indicators
Chemicals
Circuit Board Hardware
Circuit Breakers
Computers and Peripherals
Contactors
Control
Connectors
Converters (A/D D/A)
Copper Flex Products
DC-DC Converters
Delay Lines
Die and Wafer Products
Digital I/O Products
Displays
Documents
Drawings
DSP Systems
EMC/EMI Suppressors
EMI/RFI
Enclosures
Encoders
Equipments
ESD
Fan Accessories
Ferrite Products
Fiber Management
Fiber Optic Cables
Fiber Optic Devices
Filters
FPGA
Frequency Control
Fuse Holders
Fuses
Grommets and Bushings
Grounding Systems
Hall Effect Switches
Heat Shrink
Heat Sinks
Hybrid Microcircuits
Identification Products
Imaging Signal Processors
Inductive Parts
Integrated Circuits
Interface Modules
IR Devices
Joysticks
Keyboards
Keypads
Kits
Knobs
Labels
LAN Products
LCDs
Lighting Ballasts
Liquid Level Sensors
Magnetic Materials
Magnetics
Materials
Mechanical Fasteners
Mechanical Hardware
Membrane and Capacitive Switches
Membrane Keypads
MEMS
Microwave Parts
Modules
Molding
Motion Control
Motors
Office Supplies
OLED Displays
Optical Devices
Optoelectronic Devices
Oscillators and Crystals
Packaging
Panel Assemblies
Panels and Switches
PCB
PCB Products
Photo Detecters
Piezoelectric Devices
Pneumatic Parts
Potentiometers
Power Inlet Devices
Power Supply
Power Supply Modules
Printheads
Protection Devices
Relays
Resettable PTCs
Resistors
Resonators
RF Parts
SAW Components and Modules
Schematics
Security Products
Semiconductor Wafers
Semiconductors
Sensor Systems
Sensors
Shock Absorbers
Sockets
Software
Solar Cells
Solenoids
Static Control
Subassemblies
Substrates
Surge Suppression Components and Assemblies
Switches
Telecom Products
Terminal Blocks
Terminal Strips
Terminals
Test Points
Thermal Cooling
Thermal Management Products
Thermisters
Thermostats
Timing Devices
Tool Kits
Touch Screens
Trancducers
Transformers
Trigger Devices
Tubing and Harnessing Products
UPS
Ventillators
Wire Management
Wireless Communication Products
Wires
Wiring Ducts