The triple planetary crisis [1] highlights interlinked issues that humanity and multispecies currently face: climate change, pollution and biodiversity loss. For viable planetary futures, issues need unpacking in accessible and collaborative means. In contemporary times, it is critical to transition to less impactful distributed practices, external to governmental structures, based on contextual placed-based challenges. This article reports on the design of the Ecological Citizen(s) Preferable Futures Deck, focusing on ‘EC what if question creation’ for positive planetary futures and Human-Computer Interaction (HCI) interventions. Its goal is to produce inclusive, accessible outcomes with design/non-design audiences intent on bringing agency/autonomy to their communities based on co-created What if? questions. It shares insights on cross-disciplinary development of the Deck, grounded with partners and leading peers. The HCI opportunity for Ecological Citizen(s) is expansive, but it follows the transition in designers’ roles outlined by the UK’s Design Council: Systems Thinker and Connector/Convener [2]. The EC project seeks to work collaboratively for planetary futures building on; lived, place-based and trained experience(s). The in-progress workshop sessions collated feedback from leading design experts and community voices, presenting applicable reciprocal HCI lessons for to cultivate a digital sustainable society, toward positive planetary design.