The Creeping Forest:
When the island of Malu suddenly breaks off all outside contact G-Force is sent in to see what is happening. When they get there they find that the island (robot forest + human thugs) is forcing the inhabitants to mine diamonds for Zoltar. When G-Force releases the people a giant robot mole is sent after them. While G-Force uses the Phoenix to destroy the mole Zoltar escapes, leaving the diamonds behind.

The Earthquake Menace:
When an earthquake hits California G-Force is sent to investigate. While they are investigating Zoltar breaks into all communications and declares himself Supreme Commander. He threatens to cause a much stronger earthquake and send San Francisco and Los Angeles into the sea unless the earth surrenders. G-Force finds Zoltar's hidden lair and destroys it when the Phoenix transmutes into the Firebird and crashes into it. They think they have killed Zoltar but it is just a Zoltar robot. Of course, the real Zoltar gets away.