BaaS Platforms
pubnub.com
Swift, Kotlin, and React messaging at 1 million transactions each month. Transactions may contain multiple messages
OneSignal
10,000 emails/month,No Credit Cards are required
iron.io
Async task processing (like AWS Lambda) with free tier and 1-month free trial
progress.com
Mobile backend, starter plan has unlimited requests/second, with 1 GB of data storage. Enterprise application support
backendless.com
Mobile and Web Baas, with 1 GB file storage free, push notifications of 50,000/month, and 1000 data objects in the table
connectycube.com
Unlimited chat messages, p2p voice & video calls, files attachments and push notifications. Free for apps up to 1000 users
back4app.com
Back4App is an easy-to-use, flexible and scalable backend based on Parse Platform
Integrately
Automate tedious tasks with a single click. Free 100 Tasks, 15 Minute
IFTTT
Automate your favorite apps and devices. Free 2 Applets
simperium.com
Move data everywhere instantly and automatically, multi-platform, unlimited sending and storage of structured data, max. 2,500 users/month
Jamsocket
Backends for real-time apps. 
Stream
Feed and chat as a service