- Youtube -> Plaintext converter
https://www.googleapis.com/youtube/v3/captions/<id> - Arca Musarithmica web app (compose and play 17th century church music)
- Group Reddit, a group owner creates a multireddit & invites friends, friends can vote on subreddits to add or remove; bonus feature: owner has ultimate veto on what's included
- Twitter Unfollowing Tool -- get twitter "Friends" (mutual relationships) and "Following," ask which non-friend followers to unfollow.