You'll likely find that you'll get the strongest smoke flavor from using BBQ pellet blends that contain Hickory and Mesquite. 

However, due to the stronger smoke flavor, Hickory and Mesquite are normally best suited to red meats such as beef. You may find that using Hickory/Mesquite with foods that emphasize smoke flavor, such as chicken, you might not actually like the end result.

Now, a stronger smoke flavor also depends on how well your particular pellet grill/smoker produces smoke. If it has a dedicated Smoke Setting or P-Setting, you'll want to play around with that to increase smoke production.

If you're in the market for a new pellet grill/smoker, check out our database through the link below and you'll be able to search the latest pellet grills/smokers that have a dedicated 'Smoke Box' for additional smoke flavor.