During the FUAVE project funded by the Academy of Finland, VTT produced two drone swarm simulators:
SwarmOperator 
The SwarmOperator simulator was used to investigate the collective dynamics of a drone swarm in which a single unit is remote controlled by a human operator. The movement of the other members of the swarm, relative to this unit, is governed by a set of tuneable parameter values which affect the outcome of autonomous navigation decisions and support the emergence of different flying patterns (fixed regular grid, exploration, escort etc.). The SwarmOperator is meant first and foremost as a proof-of-concept for a streamlined swarm user interface. The SwarmOperator source codes in Java are openly available for download here. For more details about the simulator, please refer to Saffre, Hildmann, and Karvonen (2021).
GPSwarm
In the GPSwarm simulator you can designate targets for a reconnaissance mission and the drone swarm plans and executes the mission autonomously. By combining collective intelligence principles with the digital twin paradigm, we developed a simple yet powerful solution to the problem of allocating resources in a reconnaissance scenario. The simulated solution featured emergent division of labour, as our algorithm computes a series of complementary round trips from an arbitrary number of points of interest. The “fire and forget” drone swarm then executes the mission without any need for further instructions or supervision. More details of the simulator are available in a flyer “Collective intelligence for autonomous drone swarms”, which was distributed at FUAVE events. Additional details and the simulator source code is available from Fabrice Saffre (firstname.lastname@vtt.fi).