Certainly it can free win some games
If you controlled a creature with power 4 or greater when you declared Ruby as an attacker, it doesn't matter whether you still control one as her triggered ability resolves
Finally, don't sleep on rituals, instants (and, rarely, sorceries) that trade a card in your hand for a quick burst of mana
Its not like that exactly, but as I said about Mirkwood Bats, its easy to sacrifice artifacts nowadays and make this bat warlock huge
We have Aristocrats, self mill, Delirium (and others like Spell Mastery, Threshold) and flashback (and others like eternalize and disturb) Ogre could be interesting for all sorts of graveyard themes including reanimator and Delirium