Filestack - Simple file uploader and robust APIs for uploading, transforming, and delivering any file into your app. Filestack is a collection of tools and powerful APIs that make it simple to upload, transform, and deliver content.

intoDNS - IntoDNS checks the health and configuration and provides DNS report and mail servers report.

Elph Plasma - Highly scalable blockchain infrastructure for Ethereum

Dnsstuff - DNSstuff offers DNS tools, Network tools, Email tools, DNS reporting and IP information gathering.

Cal.com - Cal.com (formerly Calendso) is the open source Calendly alternative.

MxToolBox - All of your MX record, DNS, blacklist and SMTP diagnostics in one integrated tool.