5iler (pronounced "filer") is a minimalist notepad that gives you only 5 pages with different colours. The idea is to keep everything manageable by limiting your options, hence only 5 pages. It saves automatically to the browser's local storage, but you also have the option to syncing to your Dropbox account. Various keyboard shortcuts are available to apply formatting and create headers, lists etc.
MergeFil.es merges multiple files of varying formats (PDF, MS Word, MS PowerPoint, MS Excel, images, HTML, text files) into one consolidated PDF, MS Word, MS Excel, MS PowerPoint, or audio file. It lets you upload all required files from one folder, order them to your preference, select the output file format, then gets to work.
ZenPen is a minimalist, distraction-free writing tool. It supports only a few formatting tools like bold, italics, quotes and links. You can also toggle full-screen, invert the colors (night-mode) and set a target word count. Once you are done, you can save your work in HTML or plain text.
ShareDrop is a HTML5 clone of Apple's AirDrop. It lets you transfer files between devices on the same local network. It uses WebRTC for secure peer-to-peer file transfer and Firebase for presence management and WebRTC signaling. The ShareDrop app itself is open-source, so you can actually host it yourself if you are so inclined.