romulus.dats.site — A Rom-Manager that is worth to try.

romcenter.com — Another very good ROM-manager

emulab.it — dats download portal, great place to get the MAME dats.

mamedev.emulab.it — One of the best rommanager available on the world

mameguide.info — A very useful tool for creating MAME dat files. Full, rollback or update dats are very easy to generate. Use the created dats with a rommanager.