Location: China 
China is one of the biggest trading partner of Vietnam, its very common to see Vietnamese products in China. 
Some typicals: 
1.Instant coffee 
Vietnamese instant coffee,especially G7 is very popular in China : 
 
 
Some other brands are selling well too: 
 
 
AND 
 
 
AND 
 
 
2.Snacks 
There are lots of Vietnames snacks on Chinese online shopping websites such as  淘宝网  ,  京东(JD.COM)-正品低价、品质保障、配送及时、轻松购物!  etc 
I think Tipo (or Lipo) cream egg cookies are most popular Vietnamese snack in China.I can find them in every shopping mall in Beijing. 
I prefer Tipo: 
 
 
Lipo: 
 
 
jackfruit chips / mixed fruits and vegetables chips : 
 
 
mung bean cakes: 
 
 
durian cakes: 
 
 
cashew nuts: 
 
 
instant noodles: 
 
 
3.Electronic products 
There are also lots of Vietnamese electronic products in China but few people notice that. 
CPU: 
 
 
printer: 
 
 
For me,my camera is made in Vietnam and it works well.