Are you looking specifically for 7.6 or will the XCP-ng open-source equivalent work for your needs?
: After creating a virtual machine, remember to install XenServer VM Tools to enable better performance and management features. XenServer 7.6 - Xen Orchestra xenserver 7.6 iso download
: Reduces "boot storms" and improves performance for Citrix Virtual Apps and Desktops by caching frequently accessed data. Integrated Health Checks Are you looking specifically for 7
sha256sum XenServer-7.6.0-install-cd.iso xenserver 7.6 iso download
: Use XenCenter 7.6 (the Windows-based GUI) to connect to your host and manage virtual machines. XenServer 7.6 Now Available for Download!
If you are looking for the original ISO or related documentation "papers," here is where they can be found: 1. Download Sources for XenServer 7.6 ISO Official Product Page