What are some of the most common viruses that are associated with encephalitis?

Many. Herpes simplex virus measles virus japanese encephalitis virus west nile virus st. Louis encephalitis virus eastern equine encephalitis virus western equine encephalitis virus rabies virus (not common in humans).
Herpes type viruses. Encephalitis, inflammation of the brain, can be caused by viruses, bacteria, fungi, parasites, unknown causes, etc... Herpes types 1 & 2, epstein barr virus, varicella (chicken pox, shingles) virus, polio virus, coxsackie (hand-foot-mouth) virus, measles virus, japanese encephalitis virus, etc..., can cause encephalitis.