Configuration Management and Orchestration:

• Chef
• Puppet
• SaltStack
• TerraForm

Monitoring and Performance:

• Zabbix (Zabbix actually has an Ubuntu based Appliance, but um, frankly it kinda sucks)
• Zenoss Core
• Cacti
• Nagios

Multi node TKLs:

• OpenStack
• Hadoop

Also I think there would be interest in a couple that might need to be dynamically configured on boot due to potential licensing restrictions:

• Oracle Express Edition or Oracle 11g

Would probably need to link to Oracle downloader, and license agreement but is free to use for development and testing

• HomeSeer

While this product is ultimately a paid license product, the solution is kind of half baked in that it is distributed as an application, but really requires more of an OS wrapper around it. It's an ASP.net application and the mono TKL can probably function as that wrapper and add to it the service and systemctl aspects missing in their directions to make it just function. 

Anyway everything on this list are applications that are either somewhat painful to get working initially, or are useful for side by side product evaluations where a configuration learning curve before even getting to actually evaluating the application can make it impractical to even do evaluations in the first place.