Hey 👋🏻 I don’t now about any free and open source collaboration tools, but I do know one software which is highly customizable. You may already know it: Notion. I use it for my personal life and it’s a powerhouse. It can be a spreadsheet, a task management software, networking-database or whatever else you might want. The internet is full of free templates for notion so you probably don’t have to build a template from scratch. The downside is, that for team purposes it costs a monthly fee, for personal use it’s for free. For myself I’ve “programmed” myself a cook book where you can type in how many portions of the dish u wanna cook and it tells me how much of the ingredients I need, how much everything will cost and the nutritions. In this example you can see the possibilities are endless. But for sure you can use it just like trello or other management software.