The A.R.C is the main research group studying the anomalies occurring inside of gm_construct 13 beta. The base made in gm_construct 13 beta was one of its first bases made for closer and more direct observation, albeit not immune to the effects of some anomalies.
Other publicly know bases are the ones located in "gm_building_construct", "gm_redden", "gm_kitchen_remaster.", there are more but their locations are classified.
Overview
Documentation of Discovered Anomalies in gm_construct 13 beta