Xbox:Modding Hardware List
Stores
Chimeric Systems (sold by Kekule) - Modding tools, parts, accessories
Console5 - Parts and accessories
MakeMHz - Modding parts, repair parts
Digikey - Electronic components
Mouser - Electronic components
Services
Redherring’s Mod and Repair Services
Castlemania's list of recommended service providers for mods and repairs
Softmod Supplies
Compatible USB Flash Drive (Canadian Amazon)
USB Cable Adapter (for Game Save Exploit softmods) (Amazon)
USB Adapter for Controllers + Power Button
Hardmod Supplies
OpenXenium (sold by /u/KingLuxor)
LPC Rebuild Board for Modchips
OpenXenium (MakeMHz)
LPC Rebuild Board (MakeMHz)
Conductive Paint Pen for TSOPs
Upgrade Accessories
HDMI Video Adapter (Chimeric Systems)
XboxHDMI (fully digital video output) (MakeMHz)
StarTech IDE-SATA Adapter (US Amazon)
StarTech IDE-SATA Adapter (Canadian Amazon)
80-Wire IDE Cable (Chimeric Systems)
Custom Jewel (Chimeric Systems)
LED Jewel Light (Chimeric Systems)
RAM for 128MB RAM Upgrade (eBay)
Controller Accessories
OGX360 (on hold due to chip shortage)
Replacement Breakaway Cable (Amazon)
Controller Extension Cable (Amazon)
Repair Parts
DVD Drive Belt Replacement (Console5)
Full Capacitor Kits (Console5)
CPU Capacitor Replacement Kit (Chimeric Systems)
3D Printed Feet (Chimeric Systems)
Replacement Rubber Feet (Console5)
Other
AV Connector for DIY Component/RGB Cables (Console5)
The Black Art of Xbox Mods by Jonathan Harbour - A now-dated book of Xbox mods from 2004.