lolsuite.org — Site protected with ddos-protection. Currently in beta, written in c++14 FBneo rom repo and rom-finder forum.

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

babelsoft.net — Frontend for MAME

romcenter.com — Another very good ROM-manager

mgalaxy.com — mGalaxy is the best and easiest Mame arcade and gaming console emulator frontend layed out in a neat and nice interface.

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

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.