Skarpline is a free collaboration service to share files with coworkers and chat with them. Also supports integration with Dropbox, Google Drive, Hangouts, etc.

New York Public Library digital collections is a online collection of digitized material like photos, maps, prints, videos, manuscripts, etc. Check it out.

Firesub is a free online application to create reusable checklists and assign team members. The best features are the triggers, outcomes, and due dates.

Monolist is a free online application to collaboratively create playlist from tracks of SoundCloud, Bandcamp, etc. Discover tracks and add to playlists.

SuperBetter is an online life gamification service that helps to gamify your usual not-so-exciting day in order to make you happier and healthier.

Siftery is a free website which lets you find the tools that other companies use at work. Check it out.

ProofMe is a unique online service which is aimed at reviewing and sharing creative constructs in various formats. It also acts as a content approval service where people can comment and give suggestions on each other’s creative content when shared. These points make ProofMe a powerful platform where multiple people can collaborate on a project, where they can share their views and suggest changes on the project.

Codehalf is a free website to get you into the habit of coding everyday using notes and calendar feature. Check it out.