How would you map a refill shop on OSM? Those places you can go with containers and buy by weight.

Some popular tags or keys that could possibly apply

• Key:zero_waste
• Key:reusable_packaging
• Key:bulk_purchase

Source: https://wiki.openstreetmap.org/wiki/Key%3Ashop

These are mapped as regular shop, classified by what they sell; except that they get an extra attribute about zero-waste as m-p{3} pointed out.