G’day!
I’m the lead developer of the BlenderBIM Add-on. It is a large add-on that adds capabilities to Blender to author digital buildings compliant with ISO specifications in the architecture, engineering, and construction industry. Features include architectural modeling, construction sequencing, cost scheduling, structural analysis, drawing generation, and more. It is well over 100k lines of Python code and also about 50k lines of C++ code excluding dependencies.
We are looking for a part-time Python programmer familiar with the Blender API. It is an open source project, so any code you write will be also open source. Despite the complexity of the codebase, there are relatively simple isolated tasks, some as pure Python tasks, some as pure Blender API related tasks, and if you want, some deal with other systems too.
Our Git repo is https://github.com/ifcopenshell/ifcopenshell
There are three core devs right now, with about 65 casual contributors per year, we are not a company. Work would be on-going, with a few tasks every month. Over time, if you enjoy it, it would be great to change to full time. We prefer an hourly rate and do “as much as you can” within a few guaranteed paid days every month, but are OK with a quote on a task-by-task basis when starting out.
Due to the nature of the system we are building, I will be available to answer questions and provide guidance 
We’re very active on IRC / Matrix chat.
You can see a demo of the add-on’s capabilities here: https://www.youtube.com/watch?v=Ooh05WF__80
We have a gazillion bugs if you want an idea of the work to be done https://github.com/IfcOpenShell/IfcOpenShell/issues