This review provides an in-depth analysis of existing and emerging IoT simulators, focusing on their capabilities, real-world applications, and the challenges and future trends in the IoT simulation area. The study highlights the need for more comprehensive and versatile IoT simulators that can handle complex, large-scale scenarios and meet specific developmental requirements, such as device mobility, energy models, Software-Defined Networking (SDN), and scalability. It identifies several significant gaps in the current literature, including the lack of a generic simulator capable of simulating various scenarios across different domains, the need for simulators that address specific security concerns like battery depletion attacks, and the need for further research on the integration of IoT simulators with traffic simulation for VANET environments. Additionally, the review notes that renewable energy sources are underrepresented in IoT simulations, despite an increasing global emphasis on environmental sustainability. The study emphasizes the importance of open-source simulators to ensure accessibility and customization for researchers and practitioners. It also discusses the importance of IoT simulations in testing scalability, security, interoperability, and real-world scenarios, and highlights the challenges in simulating IoT networks, including security, energy consumption, heterogeneity, and scalability. The review concludes that there is a need for more advanced and adaptable IoT simulation tools to address the multifaceted challenges and opportunities of the IoT domain.This review provides an in-depth analysis of existing and emerging IoT simulators, focusing on their capabilities, real-world applications, and the challenges and future trends in the IoT simulation area. The study highlights the need for more comprehensive and versatile IoT simulators that can handle complex, large-scale scenarios and meet specific developmental requirements, such as device mobility, energy models, Software-Defined Networking (SDN), and scalability. It identifies several significant gaps in the current literature, including the lack of a generic simulator capable of simulating various scenarios across different domains, the need for simulators that address specific security concerns like battery depletion attacks, and the need for further research on the integration of IoT simulators with traffic simulation for VANET environments. Additionally, the review notes that renewable energy sources are underrepresented in IoT simulations, despite an increasing global emphasis on environmental sustainability. The study emphasizes the importance of open-source simulators to ensure accessibility and customization for researchers and practitioners. It also discusses the importance of IoT simulations in testing scalability, security, interoperability, and real-world scenarios, and highlights the challenges in simulating IoT networks, including security, energy consumption, heterogeneity, and scalability. The review concludes that there is a need for more advanced and adaptable IoT simulation tools to address the multifaceted challenges and opportunities of the IoT domain.