Sorry if these have been mentioned already -
Just some good old fashioned building blocks that can be used to make floors, walls, ceilings that come in a variety of textures - painted, metal, concrete, wood etc. Also in the standard small/medium/large/extra large sizes. This helps to cut down on the number of items needed to stack to create rooms/floors etc.
"Clusters" of trees, rocks etc so these kinds of things are a group of items instead of needing to place trees and such individually.
A way to rename the teleport points to something other than Greek/Latin.
A teleport point for "base exit". This would allow for people who are using teleport points within the base to exit from any point instead of needing to head back to the entrance portal itself.
A method of using objects other than the existing teleport devices as teleport points. For example, using an ordinary door as the teleport instead of needing to hide portal behind it.