Some of the books I worked off of when preparing for Pirate Nations were: 

Empire of Blue Water:
https://www.amazon.com/dp/B000PDZFCU/ref=dp-kindle-redirect?_encoding=UT...

The Republic of Pirates:
https://www.amazon.com/Republic-Pirates-Surprising-Caribbean-Brought-ebo...

The Dutch East India Company:
https://www.amazon.com/Dutch-East-India-Company-Multinational-ebook/dp/B...

James Clavell's Asian Saga (great reads, but rather Randian philosophically):
https://www.amazon.com/Asian-Saga-5-Book-Series/dp/B011M9KGG0/ref=sr_1_1_ha

And last but definitely not least,

Patrick O'Brian's Aubrey/Maturin novels that won him a knighthood into the Order of Bath (the only person who never served in the Royal Navy to have won such an award):

https://www.amazon.com/Aubrey-Maturin-Novels-21-Book/dp/B00VZIQ94C/ref=s...

There are a ton of other online resources, but those were all major inspirations for me, and helped me shape what I was thinking should go into the book.

There were tons of movies as well (PotC, Treasure Island, etc.), but I wanted to focus on the books here. :)