Recent years have witnessed increased interest in everyday forms of heritage and the emergence of alternative terms designating cultural goods, monuments, and sites on the margins of official heritage (e.g., mundane, ordinary, informal). This paper systematically compares these terminologies to explore how their marginality challenges official discourses, offering insights into epistemic shifts within the Anglophone and Eurocentric heritage domain. Through a systematic literature review (SLR), we examined academic literature on heritage categories that fall outside official vocabularies, lists, and traditional preservation measures. Two questions guided this analysis: (1) How is each heritage term defined? (2) What values do authors attribute to these alternative designations? The research highlights tensions between traditional heritage frameworks and contemporary demands for adaptive, locally relevant approaches. In response to these emerging dynamics, and to facilitate future reflections on the issues raised by our SLR, we use the notion of liminality as a conceptual lens to reclaim the marginal status of these heritages while simultaneously emphasizing their capacity to serve as a fertile ground for critical and future-oriented heritage imaginaries. The study concludes by opening a reflection on how liminal heritage practices can inform more inclusive policymaking by challenging rigid age thresholds, reinterpreting continuity through adaptation, and expanding authenticity to include transformation.