Being in charge of the thermal design and analysis for three external payloads that will fly on the ISS (EuTEF, EUROPA and LOBSTER) we highlight in this paper the commonality among them: they are attached to standard adapter plates and have standard resources in terms of power and mass allocation. These payloads, despite these commonalities have specific features due to the different scientific targets, are in different development phases and occupy various locations outside the International Space Station (ISS). Even if thermal requirements are not substantially different the different locations imply different environment and therefore different thermal control solution. Also analytical models of the ISS are different due to ISS development phase and details in proximity of payload location. The paper goes through common thermal design choices and specific solutions adapted to the specific needs of each of them. The possibility of implementing future generation payloads and the lessons learned from these processed is exploited as well.