Humans as sensors is the paradigm for transforming the idea of a "smart city" into the concept of a "cognitive city". While the concept of smart cities is based on the notion of using technology to improve city life, cognitive cities take it a step further by utilizing the large amounts of data generated by people to make informed decisions. In developed countries, numerous projects have been successfully implemented using cognitive computing models in areas such as health, transport, and energy sustainability. However, in developing countries such as Ecuador, the collection of data is often a challenge, making it difficult to implement these types of projects. Therefore, in this paper, we present a comprehensive approach to identify available data sources, including open data, social media, and IoT networks, to start the path toward cognitive cities. Our main objective is to present and facilitate the understanding of those datasets by classifying them according to their context of use around their importance in a cognitive city. In this sense, this document consolidates 547 datasets from open portals and describes several proposals in which sensors generate data as part of the Internet of Things infrastructures. Besides, we corroborated that Twitter, Facebook, and Youtube are the most used online social networks in terms of e-participation mainly. We then identified the most relevant categories based on the data available from the analyzed data sources for cities in Ecuador. The results presented establish the need to understand, retrieve and use these data by government, academic, industrial, or research entities. Thus, decision-making processes may be implemented to improve the quality of life of citizens on the basis of available data and aim at building a cognitive country.