Keychron Keycaps
These keycap sets can fit with 75% layout keyboard, and they all have additional keycaps for Windows and macOS.
Keychron Plates
Compatible with both the Q1 and Q1 Knob version
Switches
Keychron Q1 has 82 keys. If you want to build a full keyboard you need to purchase [3 * 35 switches set].