Presenton is an open-source “Gamma/Beautiful.ai alternative” that generates PPTX/PDF slide decks with AI, but can run fully self-hosted so your content doesn’t live in someone else’s SaaS. It’s gotten strong traction on GitHub (about 4k stars) because it fixes the usual pain: you want fast decks, but you don’t want subscriptions, data leakage, or vendor lock-in. The fun “see it in action” moment is uploading an existing PPTX to turn it into a reusable template, then generating a fresh on-brand deck from a prompt.