How many do you want? As long as you want only a few figures for small encounters on the scale of Gloire/Under the Black Flag, or Savage Worlds, then you can pick and choose a few that look right. If you want to stage larger battles, then you might need to buy a lot of Foundry packs.
Most of the Foundry figures from their Swashbuckling, pirates, 30 Years War, and English Civil War look fine for mid-17th Century. For late in the 17th Century, those pirates still look good, and the Foundry Early Marlburians are good too, the ones with "informal tricorns" and 12 apostles (powder flasks on a bandolier), also described as matchlock men. Dixon also has pirates and late 17th Century troops in "informal tricorns" and 12 apostles. Dixon also has a set of figures for Monmouth's rebellion, which are more informally clothed than the regular troops, and which often have open hands to allow a different weapons to be carried. Some might be usable for pirates or town militia. Dixon also makes pirates.
Short answer: Foundry and Dixon (both make high quality 17th Century figures)
Note: Front Rank is coming out with a late 17th Century line of troops, but the Front Rank figures are really bulky compared to the Dixon and Foundry figures.