Tabula Rasa planets are devoid of any monsters. They are better Barren, less inhabited Eden. For those of you who want some colour and visual pop to your bases, without having to remove the neighbours first.
Tabula Rasa ("Blank Slate") is best described as a garden sort of planet. There's typically a variety of fruit trees, garden type plants, pleasant weather, and most importantly, no surface opposition. You can wander the entire surface (which is often relatively flat) of a Tabula Rasa with no worries whatsoever; this makes it ideal for establishing colonies, bases, or laboratories.
There is a question, though. What caused the planet to become like this...?
Details
Name: Tabula Rasa
Tier: 1 - 4.4
Gravity: 70 - 90
Found around stars: Binary Star, Red Star, Blue Star