First row from left to right and then the second row:
1: Tuberculosis seal (if I am correct year 44 in Republic of China, which is in our counting 1955, making it Taiwan)
2: postal saving stamp (1941-1945), from Manchukuo, if I am not wrong.
3: Manchuria local overprint on Manchukuo stamp after surrender of Japan in 1946. These are literally hundreds of different ones. I don't have now time to try to identify it.
4: North East China postage due 1947 (Republic issue)
5: China 1948 inflation issue (Michel 878)
6 and 7: Most likely revenue stamps of Republic of China.