ThingSpeak - Open source data platform for the Internet of Things. ThingSpeak Features
Fluentd - Fluentd is a cross platform open source data collection solution originally developed at Treasure Data.
Azure IoT Hub - Manage billions of IoT devices with Azure IoT Hub, a cloud platform that lets you easily connect, monitor, provision, and configure IoT devices.
Splunk - Splunk's operational intelligence platform helps unearth intelligent insights from machine data.
AWS IoT Analytics - IoT Management
Datadog - See metrics from all of your apps, tools & services in one place with Datadog's cloud monitoring as a service solution. Try it for free.