MechKey.Org - All about keyboard

Keyboard Layout Editor - This is a web application that enables the editing of keyboard-layouts, i.e., the position and appearance of each physical key.
Keyboard Layout 3D Viewer - Render 3D keyboard from KLE json.
Keycap Renders - Render 3D keycap set.
Plate & Case Builder - Keyboard top plate CAD files generator, for keyboard-layout-editor generated layouts.
ai03 Plate Generator - An advanced plate generator which doesn't result in 13.99999mm cutouts. Also fillets the cutouts so you don't have to waste hours later.
Keyboard Layouter Plugin - Keyboard Layouter is a plugin for KiCad(pcbnew). This plugin places switch footprints in the location specified by JSON of Keyboard Layout Editor.
mrkeebs Pcb Generator - Quickly create PCB from KLE json.
Kalerator - PCB generator for keyboard-layout-editor generated layouts.
Keyboard Firmware Builder - Online QMK Firmware Builder. (2+ years behind QMK firmware master).
QMK Configurator - An open source configurator for QMK Firmware.
TMK Firmware Builder - Online TMK Firmware Builder.
Parametric Mechanical Keycap Library - Keycap and keyset construction library for mechanical keyboards, written in openSCAD.
KiCad Parts by Ai03 - KiCad Library of custom MX-Alps footprints.
KiCad Parts by Daprice - KiCad footprint library for kailh choc and MX-style mechanical switches.
KiCad Parts by Keebio - Various KiCad footprints for mechanical keyboard parts.
KiCad Parts by TMK - KiCad modules for keyboard design.
KiCad Parts marbastlib - KiCad symbols and footprints for mechanical keyboard design, can be added as a plugin.
KiCad Parts by Acheron - KiCad symbols and footprints for mechanical keyboard design.
Keyswitch Datasheets
QMK Proton C symbol/footprint for KiCad, Eagle
ESP32 KiCad Footprints
Kicad kbplacer - KiCad plugin for automatic keyboard's key placement and routing

Tools