Some of the work that I've done on WorldGen recently has been around improving how world maps look. I'm still sticking to a few basic planet types for now, and the most ecologically advanced so far is the EoGaian world. These worlds are similar to what Earth was like billions of years ago. They are warm, wet worlds which have methane atmospheres, and the most advanced form of life that they have is bacteria, which only inhabits the seas.
This particular world shows barren land, ice caps and mats of bacterial organisms covering much of the ocean surface in the equatorial regions. This latter feature would be a potential random feature this type of world could have. Some fraction of worlds will have one or more special features that make them standout from typical worlds of their kind. The descriptive writeup of the world would include a description of the feature, as well as displaying its effects on the map.