Oooooooo, it's a lot, the world's a big place!!!
However, to start you off:
Augustus was emperor at the time of Christ's death. He had contact with/fought/conquered:
The Middle Eastern power of Parthia
Hispania
Raetia
Noricum
Illyricum
Pannonia
Syria
Galatia
Cantabrians
Lusitania
Germania
Armenia
Gauls
Celts
Don't forget a lot of these names will be the Roman given versions so you'd have to look into them to see what they thought of themselves.
There are a whole host of barbarian tribes whose names come in to play in the later Roman period, presumably they existed or their predecessors did at the time of Christ, try:
Vandals
Alamanni
Huns (a branch of the Mongols)
Visigoths
Goths
Alans
Franks
Around that time in Indian you get the establishment of the Indo-Parthian empire and the establishment of the Kushan Empire. China's got the Western Han then Xin dynasties. Aborigines are alone minding their own business in Australia as are other indigenous peoples all over the world. Japan is in the Yayoi period. You're looking at the Zapotecs in Central America. The Inuits are partaking in the Dorset culture.
That should keep you going for a while!