Google Places, Google Tasks, Google Calendar, Google Contacts, Windows Live Calendar, Windows Live Contacts, Outlook Calendar, Outlook Contacts, iCloud contacts, iCloud calendar, WebDAV, CardDAV, CalDAV .

Cloud storage
Apple CloudKit, DropBox, Onedrive, Google DataStore, Google Sheets, Google Drive, Google Firebase Database, Box, Pryv, , HiDrive, Hubic, myCloudData.net, Yandex Disk

Cloud data binding
TDataSet based data binding for CloudKit and Google DataStore

Cloud image services
Picasa, Flickr, Instagram, Imgur, Cloudinary

GEO
FourSquare, Google Maps address data

Social media
Twitter, Facebook, LinkedIn, Trello

Payment service
PayPal

And much more
YouTube API, Weather Underground, URL Shortener, PushOver, Twilio, Esendex, BulkSMS, TelAPI, CloudConvert, Barcodes4.Me, Google Analytics, Google Mail, Exceptionless, Outlook Mail, Computer Vision, Emotion, Bing Speech