QSPICE is a new and fast SPICE simulator written by Mike Engelhardt (author of LTspice). QSPICE was initially limited to beta testing in May, then expecting to become open beta testing in July.

Quick start gives a quick overview of the UI and other elements of the software. Below are few more videos on the features.

Importing 3rd Party Models: https://vimeo.com/828090312/aa254d2e95

Using C++ and Verilog in QSPICE: https://vimeo.com/828086789/a7ada3a5d3