PrintStack – macOS virtual printer to queue and merge PDFs

You send prints to a local virtual printer, inspect a smart queue (rename items, check page counts), drag in extra PDFs and then merge or print the whole stack — exact workflow-level tooling that saves annoying manual merging. The app is small, privacy-friendly (developer claims no data collection) and includes useful extras like a log viewer, but the core idea is familiar and the free tier’s 5-document limit feels deliberately gating without compelling advanced features shown on the listing.