Caption - Open-source captioning tool to help find the right subtitles.
CaptionBot by Microsoft - Analyzing and describing images by a bot
Captioned - Say, show, share. Create a 60 second captioned video.
Dashmote - Dashmote bundles stock image providers to make finding stock images as easy as possible.
Caption This - Create a smart caption for your photo in a second!
Instagram Line Break - Simple clean line breaks for your Instagram captions