You'll need:
- PCB
- Plate
- Stabilizers
- Diodes (SMD or Through Hole)
- LEDs (If you want them and the PCB takes them)
- Switches
- Keycaps
- Hardware (screws, bolts, etc)
And I'm assuming you've got the basic soldering setup (soldering iron, solder, solder sucker). I've got a Hakko 936, Kester 60/30 solder (I forget the diameter), and a Hakko 808 and Soldapult.
- PCB you've sourced from GON.
- Plates can be tricky. They're not regularly stocked anywhere. You can either cut your own through a service like BigBlueSaw or another shop near you. If you're in Europe, I suggest contacting Matt3o as he's got a contact which will cut plates for him.
- Stabilizers are also tricky. I've harvested mine off old Cherry boards and bought some from Mouser. The issue is finding the 6.25x and 7x wires. I suggest hunting the classifieds or finding old Cherry boards to harvest from.
- Diodes and LEDs I get from Mouser and/or eBay.
- Switches I buy from Mechanicalkeyboards.com, harvest from old boards, or buy from GB/classifieds
- Keycaps I get from old boards or GBs
- Hardware hopefully comes with your keyboard kits but the local hardware store should be able to hook you up
Plenty of people build their own DIY keyboard kits. I think you need to look a little harder since not all of them are contact in MST. People do keyboard builds the keyboards or media subforum as well. I put my
KMAC build log in the media subforum for example.