The following things are normally apply in non-EU European countries (except Kosovo and North-Cyprus).
You need an European green card which indicates is valid in Belarus. You can get this from your insurance company. The BY-unit on the card must not be deleted, which indicates that you have a valid European Third-Party Insurance in Belarus.
You may also purchase extra insurance other than the mandatory third-party insurance. But this is not mandatory.
You need the car registration form in common European format, which you should already have one.
Car Number Plate:
You need an oval FL label stick besides your number plate.
You need your passport with a valid visa.
You need a valid driving license in common European format. You'd better have an IDP International Driving Permit for general purpose.
You may need to buy extra travel health insurance. You'd better also take your European Health Insurance Card as you will drive through EU/EWR countries.