actually reverse alphabetical order is pretty common theme-- as is all the vowels in (or in reverse) order-- or words that have all the vowels in them once, or just words that have all the vowels (not in order, and sometime more than once.

Anu (the wordsmith) has also invited people to be guest word smiths.. so if you know five words that are not yet in the archive that have an unusual theme.. He would like you to give details, (definations, citations.. but some guest word smith have done other things...) try your hand if you'd like...