Who were the imperialist powers in the 19th century?

Britain, France, Germany, Russia, and the Netherlands continued to colonize during this era, but they also devised other ways to spread their empires. In the late 19th century Japan and the United States joined the European nations as a power.

Explanation:

Their power was unity to become all one ti be more powerful as you can see in the answer.

"In the early 19th century, the Industrial Revolution began to transform Britain; by the time of the Great Exhibition in 1851 the country was described as the "workshop of the world". The British Empire expanded to include India, large parts of Africa and many other territories throughout the world."