I built an opinionated minimalist ePub/pdf online reader
Clean reader but browser-based EPUB viewers already exist.

Simple collage maker, but Canva and Figma already dominate this space completely.
Casual users needing quick image layouts
Canva · PhotoCollage.com · Fotor
Clean reader but browser-based EPUB viewers already exist.
Canva alternative with shape fills, but Canva already does this better.
Mobile GA4 dashboards when Looker Studio already exists for desktop.
Undo support for context management is a genuinely useful feature.
GUI wrapper for OpenCode config when the JSON schema is already straightforward.
Exports vanilla HTML, but another no-code builder in a saturated market.