Oddgrabber (Level 1): Take a yellow Crystal with a cost of 1 from the Mine. This action does not count as mining, therefore it does not interact with other skills or Artifacts that affect the Mine action.
Drollo (Level 2): Gain an additional mining action this turn. For example, if you play this card as your first action, you can perform an extra mining action this turn in addition to your normal second action (which could also be to Mine). If this card is your Leader, you can perform three actions in your turn, one of which has to be the Mine action.
Robuster (Level 3): Temporarily change the color of up to 3 cards in your hand to any one color. This is useful for mining Crystals as you need to play cards that match the color of the Crystal.
Scrabber (Level 4): Take a second Crystal with the same cost from the Mine after mining. This only applies to Crystals with a mining cost of 1, 3, and 6.