I live in Gmail - tight inbox, labels for everything - and kept hitting a wall where labels just turned into smaller piles. I wanted section headers inside a label so I could organize my email however I wanted, and the ability to add context/next steps to emails. All the other tools wanted full-mailbox access to do that, so I built this for myself and some friends told me to publish it :)

Shelf is built as a page-overlay with just one permission (storage) - no API, no OAuth, no server, no analytics.

- Sections create groupings however you want, notes live in local storage, and it draws in Gmail's own visual language so you should hardly notice it's there; making it feel native felt important.

Honest limitation: chrome desktop only, no mobile

Free: https://chromewebstore.google.com/detail/dgomdjjoogkknnggfbggcdnlogkhdpng

Source (GPL-3.0): https://github.com/gpon505/shelf-for-gmail

60-second demo: https://www.youtube.com/watch?v=kPMgNId_teE

Not trying to make money, just hope this is useful to some other people -- let me know if it is!