Every candidate has at least one list for their viva.
It could be a list of typos they’ve found or ten papers they think have made the most contribution to their research. Maybe it’s a to-do list for viva prep or a must-have list for their viva day. A list of questions to ask their supervisor or a list of questions they think their examiners might have for them.
There’s at least one list you’ll think to write for your viva. And while you don’t need to do anything to prepare until after submission, you also don’t need to wait to capture things on a list for later.