Rare Resources(ingredients) are a crafting component required for crafting higher-end jobs and are the currency of Smugglers.
Currently, there are three ways to obtain them. You can either loot them from some fights, buy them or find them during exploration.
The Different Ingredients
There are 10 rare ingredients in the game. One for each faction and the Star ingredient.
You will obtain a faction's ingredients by killing its associated flagships. Clearing Abandoned Space Stations also rewards random faction ingredients.
All ingredients can be looted or bought.
Obtaining
Looting
The only ships that drop crafting ingredients are flagships. The number of ingredients obtained from a flagship depends on its veteran marks.
If a ship has zero veteran marks, it will drop one faction ingredient.
If a ship has one veteran mark, it will drop one or two faction ingredients.
If a ship has two veteran marks, it will drop up to four faction ingredients and one or two Star Ingredients.
Buying
Buying ingredients is not recommended, as credits become very useful in the later stages of the game.
All ingredients can be bought in Smugglers' Bases with random availability. The Star Ingredient costs 30.000 credits and the faction ingredients cost one Star Ingredient each. This makes buying any kind of ingredient from Smugglers very ineffective.
Exploration
As of patch 0.10.0, you can get Star Ingredients by exploring barren planets' crash sites, although it is very rare.
Version 0.10.9
As of patch 0.10.9, all ingredients(other than star) are replaced by alien technologies. They currently have no purpose.