PICSimLab is a realtime emulator for PIC, Arduino, STM32, ESP32, ...
Digital Circuits Design and Simulation
Schematic circuit editor for VLSI and Mixed mode circuit simulation.
Interactive 3D Layout Viewer for GDSII
ePnR is an IC block standard cell placement & routing tool
Caneda (Circuits and Networks EDA) is an open source EDA software.
graphICs is a converter transforming GDS II-data to Asymptote-code