Do note that this is pre-print so not peer reviewed. Take it with a pinch of salt until it gets peer reviewed

There are many but the ones that I'm familiar with are mostly somewhat uncommon (I can't really list all them off the top of my head but I've done research on localized brain injury and one of the standard reasons for injury in the datasets I've worked with was viral infection). Herpes is actually one; enteroviruses are another example; there are others.

The pathophysiology of COVID kind of makes sense in terms of cognitive impairments, especially given loss of smell being potentially (often probably?) mediated by olfactory bulb damage. There's a prototype of SARS-CoV-2 infection progression that begins in the nasal cavity and sinuses and progresses downward (this is one reason for a renewed focus on nasal spray vaccines). This sort of process is not uncommon in virally-induced brain injury; the viral infection starts in the head, and progresses into the brain. The olfactory bulb area is a common culprit, as it's close to the nasal cavity/sinuses, and in the frontal area of the brain and close to areas closely linked to "higher level" reasoning and similar cognitive processes.