Home Is Where the Heart Is
Colonize one of each type of planet in one game - by C0ldSn4p

What counts towards it:

Colonizing a Planet in a new System with a Colonizer, Celestial Vines, Arks etc...

Colonizing a Planet in a Colonized System using the System Production Queue 

Receiving Planets through basically any mean (quest, assimilation, invasion etc...)

What does not counts towards it:

Terraforming an existing Planet

I hope this helps :)