The Elektor design from a few years ago was essentially an "evolved" take on the Arduino Uno R3 board, with an identical form factor as the Uno but based on the ATmega328PB-AU (see the "B"). As ...

Arduino chooses 32bit Renesas Coretex-M4 for new Uno The Arduino Uno R4 is to have a Renesas RA4M1 32-bit Arm Cortex-M4 microcontroller, and there are “no plans to discontinue the popular Uno R3” , ...