Note that “unusual and not documented” does not mean “wrong” - many should be simply documented.
Some may be fixable remotely:
clear typos (shop=suupermarket)
written in language other than English but with clear mapping to local language (for example shop selling meat in Polish is “mięsny”, so shop=mięsny is clearly shop=butcher)
too specialized tags (shop=coal is better tagged as shop=fuel fuel=coal, shop=office_furniture as shop=furniture furniture=office, shop=indian_spices as shop=spicescuisine=indian)
very clear duplicates (shop=hypermarket vs shop=supermarket)
shop with website, maybe even linked in OSM object, that allows establishing proper value of shop tag
in some cases something is clearly not a shop (shop=factory_producing_widgets is likely man_made=works)
needed and valid shop value that should be documented at OSM wiki
Some may require resurvey, if one is luckily in your area you can check it. Or you can create a note and wait for local mapper to resurvey it.
Contacting original mapper may make sense.
Remember, it is better to not edit than break data in case of tagflidling - create note if unclear or unsure.
Let me know if this list is useful but outdated (I will setup refreshing it in such case) or pointless/problematic (I can delete it if it is causing more problems than benefits).
Some improvements can be made to this list… Mayvbe mark cases with nearby notes opened already so these can be skipped for now? And mark cases where website link is available so these can be processed first?
Cases on "entries from list of suspicious ones: " list can get explanations why this values are treated as invalid. Maybe more.
(helping here is useful as it allows to reduce number of not needed and pointless top-level shop values, on 2023-08-14 we had 11 215 distinct shop values, vast majority bogus, broken or not needed. Reviewing such lists also allows us to spot missing shop values, problems with documentation and presets. Repeated appearance of shop value may indicate that wiki or presets should be improved. Maybe iD translation is bad or requires additional aliases for easier search? Maybe OSM wiki would benefit from translating it to local language or being more clear?)
(I can also generate such listing for other areas, let me know if someone is interested)
Thank you for raising these cases. Those who want to address the issues that can be resolved remotely just need to raise their hand. For the other cases, perhaps someone could step forward and make suggestions?
Far as I could tell from the signage on-site and a look online, Distributions Pla-M is a company that specializes in selling cleaning supplies. I couldn’t find any tags on the wiki that adequately covered that specific type of store, so I went with an undocumented value that had some (minor) existing use in the region. I’d be happy to implement any replacement if you know of a better set of tags!
Sorry for taking so long to reply, life got in the way for a sec. I think shop=cleaning_supplies makes sense as a tag name. I also checked the following with a quick&dirty overpass query over most of North America:
(Note that these categories are based on my perception of the name field, and in some cases a quick google search. Not necessarily super-accurate, but gives a general idea)
Going by that, I’ll update the local shop to use shop=cleaning_supplies and see about checking and updating some of the other nearby instances of shop=cleaning & shop=cleaning_supply over time (may be some delay on that though). Beyond that, there’s the wiki documentation. I’ve not done much wiki editing, is it as simple as opening a new page to describe the tag usage in the same vein as other instances of shop=, or is there more to it?