So, if you are interested in a specific set(s), of POI then what are the available options? These are typically third party providers who supply such files. Some files are claimed to hold more than a million POI data in them. The websites that sell these POI files usually have their own products, of course. Most often they also have a forum where people can and do contribute special interest POI files. A couple of sites that have been picked from top search results are POI Factory and POI Directory. These provide a source of a rich variety of POI data. These are illustrated to indicate the kind of products that are usually available. The forums available at such sites provide a means to find any esoteric needs you may have and the special POI data that is not commonly available.
The POI Factory has a rating system based on popularity, and it lists these categories. Recent categories are WalMart, Sam's Clubs, and WalMart Supercenters in the US and Canada, rest areas, and places to visit in the US. One category that is rising fast is the locations of Rite Aid Pharmacy. Some fifty odd categories are listed on a wide range of topics. A sampling of the categories will give you an idea of how wide a range these cover. The categories include airports/aviation, astronomy, ATM/banks, beer/breweries/distilleries, boating, camping, grocery/convenience stores, health clubs/gyms, hospitals/ERs, libraries, and so on. What is interesting is there are several files in each category, sometimes in the hundreds. Categories of POI files also include such very niche interest areas as where red light or speeding cameras are located.