It doesnt have the most flashy payoff, but getting through 12 toughness on the ground might take an Eldrazis strength some game so dont look down on it
Ixalan will bring a whole fleet of ne Pirates to the table, but I suspect well need to wait for the second set to have enough options for a deck that isnt stretched paper-thin
Any "as [this permanent] enters the battlefield" or "[this permanent] enters the battlefield with" abilities of the chosen token will also work
In each of these meld pairs, there is a card that explains how to meld the two cards
Thriving Heath, Thriving Isle, and Thriving Moor are very clever design, offering the player a good deal of flexibility
Later, you can sacrifice them for Goblin spells like Siege-Gang Commander, make them legitimate threats with Goblin Trashmaster or Goblin Warchief, or turn them into mana with Nothing like ramp in a red deck