If you know of something that should be listed here, please tell it the kde-i18n-doc mailing list,
Pology by Chusslove Illich: powerful framework for consistency checks, making glossaries, managing translation.
PO Summit is the concept that can significantly increase consistency of your team translations and save your time on merging the translations in various branches.
An index of on-line dictionaries and a lot of other resources can be found at www.yourdictionary.com.
Finally a tip: in the German team they are not using their mailing list but a web forum for discussing difficult translations (one term per thread) which has the advantages: (1) that everybody can jump in without the need to subscribe to a mailing list (2) and everything is pretty well documented and easy to find for translators to come.