In the days before Android, buried deep in the network settings of my old phone were two options called Preferred Networks and Forbidden Networks was an option called Preferred Networks, and I have also heard of Forbidden Networks. These were used for roaming: when the home network was not available, the phone would not simply grab the first available network but compare the list of currently available networks to the Preferred & Forbidden Networks: it would never try to roam into a forbidden network, and if one of the visible networks was on the Preferred Networks list, it would try that network first. The lists were stored on the SIM.
Note that this has nothing to do with APNs or network types – this setting is entirely about network operators.
Does Android still use these lists? If so, is there a way to view/edit these lists on Android?