Splinter Cell: Blacklist sees the return of stealth-action gameplay. Much like previous games in the series, Blacklist comes with a host of collectible items, which in this case come in the form of Dead Drops, Blacklist Laptops, and High Value Targets (HVTs).
Prolific YouTuber PowerPyx has put together video guides on how to find each of these collectible items, with the locations and instructions for each.
Dead Drop Flash Drives
There are a total of 24 Dead Drop flash drives in Splinter cell Blacklist, acquiring all of which will give you the Intel Acquired achievement and provide you with extra money to spend on your gear. Almost every mission in the game has a Dead Drop, but there's never more than one each mission.
There are 23 Blacklist Laptop collectible items scattered throughout the game. Finding them all rewards you with the Data Security achievement. Interestingly enough, the only way to acquire these laptops is to reach them undetected, or they will be destroyed by enemies before you can hack them.
High Value Targets
There are a total of 20 High Value Targets, or HVTs throughout the game. They are special characters whom you must find and capture. Capturing them all will reward you with the HVTs Secured achievement and give you money to spend on your missions.
HVTs move around during missions, but stay within certain areas, so your experience may vary from the guide above. These characters are marked differently than other enemies on your minimap and are highlighted with a larger red symbol. If you purchase the Command & Control upgrade for your airplane, you will be able to identify them more easily.
You must use non-lethal means to capture HVTs, so knock them out or use a stun gun.