https://www.msp360.com/ backup provisioning addon

Livedrive.com Cloud Storage Backup Solution for home and business backups

Mumble server provisioning addon

Teamspeak / TeaSpeak server provisioning addon

http://www.leaseweb.com/en server management addon

Manage your online.net dedicated server using whmcs.

Sermepa/Redsys payment gateway

Gandi.net Domain Registrar For WHMCS

The ChartMogul synchronization addon will synchronize your whmcs data with chartMogul.com to automatically calculates (in real time) all the key metrics you need to run your business.

https://oneprovder.com server management addon

Admin and provisioning addon for WHMCS that allows you to sell Leaseweb.com VPS servers to your clients