1) AaaS - Analytics as a Service
On demand analytics services. Web-based analytics applications.
2) BaaS - Business as a Service
Business Intelligence As A Service
Backup as a Service
Backup as a Service offers companies the ability to do their backups to the cloud.
3) CaaS - Computing as a Service
Verizon offers computing as a service, addressing Security, Reliability, and Control.
Communications as a Service
Gartner defines CaaS as IP telephony that is located within a third-party data center and managed and owned by a third party.
4) DaaS - Data as a Service
DaaS is based on the concept that the product, data in this case, can be provided on demand.
Desktop as a Service
Outsourcing of a virtual desktop infrastructure (VDI) to a third party service provider.
5) EaaS - Everything as a Service
From simple office documents to extensive customer service management, EaaS vendors could provide the tools through the cloud (internet).
6) FaaS - Fraud as a Service
When an online fraudulent activity such as trojans is provided as a service.
7) GaaS - Gaming as a Service
Gamers who may wish to either complement their existing gaming console or replace it altogether with a Gaming-as-a-Service (GaaS) option.
8) HaaS - Hardware as a Service
A service provision model for hardware that is defined differently in managed services and grid computing contexts.
9) IaaS - Infrastructure as a Service
One of the commonest and earliest form of -aaS. Provides hardware infrastruture as a service, hence in early times Hardware-as-a-Service (HaaS) was used interchangeably.
10) JaaS - Jobs as a Service
Jobs as a Service for an effective job hunting and decision making
11) KaaS - Knowledge as a Service
An on-demand, bite-sized, where-needed approach to skill acquisition.
12) LaaS - Logging as a Service
Log management in the cloud
13) MaaS - Mashups as a Service
When SOA meets web-2.0.
14) NaaS - Network as a Service
SaaS (software as a service) web 2.0 model to mobile operators and the intelligence stored within their networks.
15) OaaS - Oracle as a Service
16) PaaS - Platform as a Service
Something that stays in between software application and infrastructure as service (SaaS and IaaS).
As providing our WSO2 Carbon middleware Platform as a Service over the cloud, we have discussed this several times before over this blog itself. Hence omitting further discussion mow. :)
17) QaaS - Query as a Service
Quality as a Service
18) RaaS - Recovery as a Service
Allows you to keep and maintain ongoing backups and data recovery files.
Routing as a Service
Replication as a Service
Provides replication through the cloud infrastructure as a Service
19) SaaS - Software as a Service
Application in the cloud. Along with infrastructure as a service, this is first among as-a-service.
20) TaaS - Testing as a Service
Many organizations including Wipro and Qutesys provide testing and quality assurance using the pay-as-you-go model.
21) UaaS - Utilities as a Service
22) VaaS - Virtualization as a Service
VaaS offers low cost virtual servers using enterprise class hardware in secured datacenters.
23) WaaS - Wireless as a Service
24) XaaS - Anything as a Service. Mostly used as an umbrella term (xaaS) to refer to all the -as a Service terminology used.
25) YaaS - You-as-a-Service
26) ZaaS - Zebra as a Service
Feel free to provide reference to any other as-a-Service of the form xaaS that I may have missed in this list, as a comment below. I have come up with this list using the help of Google. So if your aaS is far below in the Google's ranking, most probably I would have missed it. Moreover you can find many similar lists of aaS online. I have found one myself before. However most of them are outdated lists and doesn't contain the new emerging or made-up xaaS acronyms or terminology.