Tricky question. Obviously, we deal with national teams, and everything which is or resembles a national team is in.
So we've got a core of fifa-approved countries and non-fifa countries that regularly play fifa countries. Examples would be Martinique (who are even a strong regional force when they take part in the gold cup), Greenland, Zanzibar, Reunion, East Timor or Tuvalu. All of these will probably become fifa members over the next years anyway.
Then we have territories that regularly compete in cups (Some of them quite old, like the Channel Island Cup) or friendlies, and very much resemble "normal" national teams. This includes all of the teams which compete in the Island Games, like Sapmi, Gotland, Falkland or Guernsey. Also in this category are territories that seldom play friendlies, but are clearly independent or overseas territories. This takes care of the Vatican, Saint Pierre et Miquelon, Mayotte or Micronesia.