PenPal World - Connect with people all over the world

Haystack Search - Haystack helps you make the most of your time, by searching all your files and documents in the cloud in one place. It's been built for privacy from the ground up, so your data isn't stored on a server, just your computer.

Unbordered - Unbordered app comes up with features to help you in finding the perfect language practice and exchange partners so you can practice foreign languages right through your mobile phone.

MailJack+ - Send PDFs as postal mail

Anygram - Anygram app offers features that let you meet new people so you can make new foreign friends practice native languages to learn something new.

Paperkit - Create and download custom graph, lined, or dot grid paper