What things make sense to be consumed collectively?
This is up to citizens in a participatory economy to democratically decide. A society could choose to have no collective goods at all, or they could choose to have many.
However, some things make a lot of sense and are more efficient and environmentally friendly to be consumed collectively. For example, things like parks, libraries, transportation, education and healthcare. This could also include less obvious things, for example a digital music streaming service or a community kitchen.
We can expect citizens would choose a greater amount of public goods in a participatory economy than exist today, because having membership and a direct decision-making say in one’s neighbourhood consumer council enables people to express their preferences for collective consumption much more easily.