Cryotic is a resource in Warframe using in the building of weapons, Warframes, and equipment. It can only really be farmed efficiently in one place, Excavation missions. During Excavation missions, you need to travel to the marked waypoints where an Excavator will be called in. You then need to defend the Excavator from waves of enemies, while keeping it powered using Power Cells that enemies will drop when they are killed.
If the Excavator survives until it completes the dig, you will be reward 100 Cryotic. If the Excavator is destroyed before reaching 100 percent, you will be awarded Cryotic equal to the percentage value it had reached when it was destroyed.
The best place to farm Cryotic is Hieracon on Pluto. This is an Excavation mission against the Infested, so you don’t need to worry about anything interfering with your defensive based Warframes. Frost, Gara, and Khora are all excellent options to defend the Excavators, but Khora with Pilfering Strangledome is especially useful, as she will cause enemies to drop more Power Cells.
Hieracon is also an excellent source of Axi and Neo relics, so the farm can double up as a Relic farm as well.
Cryotic will be affected by the booster that doubles your resource pickups, but this will not change the onscreen message. It will say you got 100 Cryotic, but if you look carefully at your resource count, you will notice that the Cryotic has been doubled. The same applies to a Smeeta Kavat and any benefits from its Charm ability.