4 layers90 × 54.7 mm

1st ESP32 Demo project
ashfaque-ur-rahman/ESP32-Multi-Sensor-PCB
ESP32-based multi-sensor PCB with temperature/humidity, light, and microphone sensors — 4 layer Board — KiCad design based on Tech Explorations tutorial
87 parts
KiCad boards from 3 GitHub repositories tagged “4-layer-pcb”, the most starred first; open any of them in PCBKit.

ashfaque-ur-rahman/ESP32-Multi-Sensor-PCB
ESP32-based multi-sensor PCB with temperature/humidity, light, and microphone sensors — 4 layer Board — KiCad design based on Tech Explorations tutorial

ashfaque-ur-rahman/STM32WB-RF-PCB-Design
STM32 microcontroller PCB design with RF capability —4 layer Board —KiCad project based on Phil's Lab tutorial series

OscarBazylewich/STM32_Audio_Spectrum_Analyzer_CustomPCB
This repository contains a 4-layer KiCad board for the STM32 Audio Spectrum Analyzer. The board has an STM32L4Q5CGT6 MCU and an I2S MEMS microphone (ICS-43434).