in the past weeks i worked on a tool that creates active and passive electronic filters based on the inputs a user makes. You can choose from a wide variety of pole calculations as well as a few different architectures. The Program looks like this:
For the output format you can select for example a Eeschema format which has everything preset to be evaluated with its current NGspice. Of course you can also decide to create a simulation file for LTspice or just output plain text.
The GitLab repo is located here and you can find pre-build versions of the program for Linux and Windows based systems on my Website. I tested the builds to run under Windows 10, Fedora 31, Ubuntu 18.04 and 19 but they should run on almost any distro.
I hope my program can be of good use to someone, i have applied a GPLv3 License to it so it should be easy to integrate in other Projects. Let me know of your thoughts and maybe we can work together on a future version