This study aims to assist in the identification of suitable key performance indicators (KPIs) that can be used to assess the sustainability performance of buildings given their transition into zero-carbon, resource-efficient, and resilient structures. To that end, a four-step methodology is proposed in this work; the first step includes the development of a KPI repository, which builds upon commonly accepted targets derived from the needs of different stakeholders as well as targets imposed by external factors. The second step refers to the expansion of the initial KPI repository, capitalizing on information from the literature. The third step includes the refinement of the repository based on predefined criteria (relevance, availability, measurability, reliability, and familiarity) and tailored feedback from key stakeholders. The final step concerns the development of KPI cards, which include all the necessary information for understanding and estimating the KPIs included in the final repository. This four-step methodological approach implementation was tested during the EU-funded HORIZON project ‘InCUBE’. The implementation of the first two steps of the proposed methodology resulted in a pool of 68 KPIs. Nearly half of these KPIs were extracted from Step 1 to fully support the monitoring of all InCUBE outcomes, while the rest of the KPIs were extracted from highly relevant Horizon frameworks, the B4P partnership, Level(S) framework, publications, and ETSI standards (Step 2). The implementation of Step 3 resulted in a shortlisted KPI pool which eventually defined the final InCUBE KPI repository, including 31 KPIs. To help with the coordination of the data gathering process and a shared understanding of the sort of information to be monitored among various stakeholders, selected KPI cards (Step 4) are presented.