There are 2 repositories under kicad-breakout-board topic.
HydraBus open source multi-tool for anyone interested in learning/developping/debugging/hacking/Penetration Testing for basic or advanced embedded hardware
SMD to THT Breadboard Adapter PCB's for QFN, TQFP, LQFP, SOIC, SSOP, TSSOP, MSSOP and VSSOP.
a series of Schematic & PCB Layout Cases base on KiCad 6.0 .
Repository for PCB Design Projects
1/2 channel 4-20 mA to voltage converter boards using LMP8640 current sense monitor.
KiCad breakout board to make it easier to put rotary encoder on breadboard. Using SparkFun symbol and footprint by @mcous.
A GameBoy card slot breakout board.
Miscellaneous/utility/convenience hardware by Gekkio
Breakout board for the XL7105-SY-B 2.4GHz RF transceiver module
A simple mic preamp for interfacing a balanced microphone (3-Pin using XLR Connector) with PC Sound Card or other gear. This PCB Design is double sided. If you have any question, feel free to ask :)
My place to store and improve KiCad boards and schematics
Breakout board for the SC16IS752.
Open-source breakout board for the inexpensive BC660K modem by Quectel
A MIDI Breakout board for Arduino
Breakout board for the A7139 433MHz RF transceiver module
STM8S003F3 Breakout board and Simple STM8 C examples with the SDCC compiler
StudyTableProject
Project-LabAnalogDesign2
Breakout board for the CC2500 2.4GHz RF transceiver module