Here you can find the information you need about the specialists in MGSV. Specialists are soldiers you can recruit that have special skills that usually unlock new items for you to develop (list of all the unlockables in MGSV). Some of the specialists can be found during main missions and some are acquired from side ops. Some of them volunteer to join you and others must be fultoned.
Mission 10 “Angel with Broken Wings” has bonus objectives to rescue prisoners from the 2 different compounds. This mission is an excellent way to get an anesthesia specialist, a transportation specialist and a mechatronics specialist.
Note: If you do not have the side op missions to find the specialist you want then finish some more side ops and free up room for the specialist missions to appear.
The cybernetics specialist gives you new research options for upgrading your bionic arm. You can find him during mission 9: Backup, Back Down
The zoologist unlocks various upgrades to make capturing animals easier (very useful if you want to catch em all!). She can be found during mission 14: Lingua France. She is being held a prisoner in the camp. 2 guards will interrogate her. Take care of them and fulton extract her to safety.
The legendary gunsmith allows you to customize your weapons. The mission comes in several parts as the first person you extract turn out to not be the correct target. You can find this mission in side ops: 107 – Extract The Legendary Gunsmith. Go to the location shown on the map below and find the patrolling target. His path takes him through the centre of the village(Masa Village, Angola).
Use Quiet to scout the village and then extract him. You will get a message saying it was the wrong target and a new location.
The new location is the Central Base Camp in Afghanistan. He is being held prisoner and requires rescuing. Once you extract him you will be able to customize vehicles. Sadly, this is still not the correct target and you will get a third (and final) location which is in Yakho Oboo Supply Outpost in Afghanistan. He is being held inside. Once you extract him you will finally have the ability to customize your weapons.
Extracting the Legendary Gunsmith early in your playthrough allows you to start customizing your guns a lot sooner.
This specialist allows you to develop tranquilizers for your weapons. Found in mission 10 “Angel with Broken Wings”. The anesthesia specialist is one of the prisoners you can choose to rescue for the bonus objectives.
This specialist allows you to develop Cargo 2 Fulton Upgrade. You can get one of these as early as mission 10 as one of the prisoners in “Angel with Broken Wings” is also a transportation specialist. You will also encounter a couple more during the next missions and finally a volunteer with this skill will join you after mission 16.
This engineer enables you to devlop the Battle Dress and other similar equipment. He is the optional prisoner in mission 14 “Lingu Franca”.
This specialist allows you to develop the knife for D-Dog and the Battle Dress for D-Horse. He is the optional prisoner (the one being transported in a jeep) during mission 9 “Backup, Back Down”.
More specialists will be added
If you know of more specialists then comment below and they will be added.