OK, the Ultimate Deployment Appliance was created in 2006,
but the latest answer in its thread was on 2015-11-28,
not so long ago, I think.
However, my question concerning appliances is more general.
As I remember, on the Marketplace there were many interesting appliances created by users,
and some of them were really unique, for example an appliance named like "How net works"
created for educational purposes (probably it was a demo showing how the computer network is working).
Also, there were available virtual machines prepared for special needs,
minimized in size, containing many useful and preconfigured tools, etc.
The current Marketplace https://marketplace.vmware.com is named as VMware Solution Exchange,
and seems to be designed for VMware partners and not the community users.
So I wonder if there are still available any appliances created by the community users,
because the old URLs doesn't work.