My favourite two low mana earth cards are "Brownie" and "Failed Summoner"
Brownie
Brownie comes in whith just 1 mana cost and makes your team 1 point faster. In combination with Creeping Ooze which cost also just 1 mana and makes your enemies 1 point slower, you can have a big advantage with your earth team.
Failed Summoner
The Failed Summoner is one of my best Earth cards, because of its low mana costs and advantage in low mana fights against a magic team, but also in combination with Mylor Crowling, this card have a very good performance!
What are your experience with this cards? Please leave a comment :)