What happens if at some stage you have to analyze a sample that doesn't belong to any of the architectures mentioned? There are many other options available at the moment and will very likely appear in the future, and as long as there is a meaningful amount of devices (or these devices are of particular potential interest to attackers), and especially if it is pretty straightforward to add support for them, sooner or later the new malware family exploiting their functionality may appear.
In this section, we will provide guidelines on how to handle malware for virtually any architecture.