One of Warframe's tougher resources to farm are Eidolon Shards. These are tied to endgame bosses that roam the Plains of Eidolon on Earth. You'll need to progress through the story until you complete ...

Archon Shards are used to upgrade your Warframe via the Helminth system. They can be embedded in your Warframes, giving you more bonuses such as more ability strength, duration, efficiency, cast speed ...