Dynamic contracts were added with the Chapter 2 release as part of the free update (not the paid Lost Harvest DLC).

Put simply, these are repeatable contracts offered from dynamic, or randomly generated NPCs all over Hagga Basin.

To find them you have to do a bit of exploring, but once you do they are pretty easy to spot (or hear).

Just look for the red flare:


All the different NPC "camps" will shoot a red flare up as you get close to them, making it pretty easy to spot (or hear). The only exception are the Pilgram camps, which have no flare.

Pilgram Camp:

Each sector of Haggin Basin will randomly spawn any number of these "camps." At any given time a sector can have none, or all of the random NPCs, and in some cases they can all be right next to each other!

There are some exceptions that I have observed:

1. Hagga Basin South does not spawn any dynamic NPCs
   
2. Jabal Eifrit Al-janub (aka Eifrit South) does not spawn any dynamic NPCs
   
3. Sheol only spawns one dynamic NPC, the Stranded Sheol Merchant.

Whichever sector the NPC spawns in will determine which contract is available at that time.

Spawn locations are completely random per sector, however I have observed more frequent locations for NPCs to spawn at than others. I suspect player base location might influence this, and have seen various results from sietch hopping.

The respawn times (rather, when they change location) is hard to pinpoint exactly, due to the fact that they literally respawn in a random location anywhere on the map: they roughly switch locations every 10-20 minutes (need confirmation).

Contracts:

• Ghoul in the Eastern Gap: Eastview Target
  
• Ghoul in the Eastern Gap: Another Eastview Target
  
  
• Ghoul in the Western Gap: Flatrock Outpost Target
  
• Ghoul in the Western Gap: Another Flatrock Outpost Target
  
  
• Ghoul on Rift's Edge: Northern Bunker Target
  
• Ghoul on Rift's Edge: Another Northern Bunker Target (not found yet)
  
  
• Ghoul in the Rift: Abernath's Descent Target
  
• Ghoul in the Rift: Another Abernath's Descent Target
  
  
• Ghoul Eifrit East: Darkwood Depot Target
  
• Ghoul Eifrit East: Another Darkwood Depot Target
  
  
• Ghoul Eifrit West: Eastern Jumble Target
  
• Ghoul Eifrit West: Another Eastern Jumble Target
  
  
• Ghoul on the East Wall: Ironwatch
  
• Ghoul on the East Wall: Another Ironwatch Target
  
  
• Ghoul on the West Wall: Sentinel City Target
  
• Ghoul on the West Wall: Another Sentinel City Target
  
  
• Ghoul in the O'odham: Rockwarren Village Target
  
• Ghoul in the O'odham: Another Rockwarren Village Target
  
  
• Ghoul at Mysa Tarill: Mysa Tarill Target
  
• Ghoul at Mysa Tarill: Another Mysa Tarill Target

Contracts:

• Pilgrims in the Gap: Dalvia's Totem
  
  
• Pilgrims on the Wall: Dyrban's Totem
  
  
• Pilgrims Among the Saguaro: Milya's Totem
  
  
• Pilgrims in the Sheol: Khrysmal's Totem
  
  
• Pilgrims in the Rift: Mirrabon's Totem
  
  
• Pilgrims in the O'odham: Bedghar's Totem

Pilgram contracts are not repeatable, they are one and done.

Contracts:

• Flyswatting (East/West Shield Wall)
  
  
• The Culling (Eifrit Al-gharb, Al-sharq, Al-janub)
  
  
• The Cleansing (need sector)
  
  
• Iron Ore Shipment (East Vermillius Gap)
  
  
• Erythrite Delivery (Eifrit Al-gharb, Al-sharq, Al-janub)
  
  
• Erythrite Delivery: Bene Gesserit ( Eifrit Al-gharb, Al-sharq, Al-janub)
  
  
• Justice For a Bike (O'odham)
  
  
• Optional donation: Iodine Pills (East/West Vermillius Gap)
  
  
• Optional donation: Welding Torch (O'odham)

• One Man's Trash (need sector)
  
  
• Scraps for the Anvil (East Vermillius Gap. Eifrit Al-janub)
  
  
• Pieces for Pinnacle Station (Eifrit Al-sharq, Al-gharb)
  
  
• Crossroads of the Junkyard (O'odham, Mysa Tarill, East/West Shield Wall)
  
  
• Optional donation: Large Fuel Cells (All locations)

Contracts:

• Irradiated Goods: Anvil (Sheol, Mysa Tarill)
  
  
• Irradiated Goods: Crossroads (Sheol, Mysa Tarill)
  
  
• Irradiated Goods: Pinnacle Station (Sheol, Mysa Tarill)
  
  
• Irradiated Goods: Jasmium (Sheol)
  
  
• Irradiated Goods: Sheol (Sheol, Mysa Tarill)

Both the Stranded Junk and Ore Merchants offer an optional "turn in" dialogue.

It would seem these objectives are not needed to complete the contract chains, as they are not tracked on the contracts list, but rather they are options to complete via dialogue with their respective NPCs for some solaris and experience.

The Junk Merchant will request a Large Fuel Cell at any location.
The Ore Merchant will request either Iodine Pills or a Welding Torch, depending on their location.

Keep in mind that if you select any of these options, the "normal" contracts they offer will then be locked out for this spawn location. In other words: you'll have to find them in another location to pickup their "normal" contracts.

I have noticed a few threads where people have commented on bugged contracts not completing, specifically for Lost Harvest and the new dynamic NPC contracts.

While it is certainly possible your journey, dear reader, might be bugged, it is also likely you actually have not finished all the subsequent, linked contracts for whatever contract is still showing in your journey screen. Compare your journeys with my list to verify.

Complete example:

Incomplete example: