Quote from kcolloranYes, glorious anthem effects are useless without any creatures on the board. So are equipment. But they are both very powerful effects in most games of magic because they help you win combat so much. Anthem effects are high picks in regular draft because they're really strong.
As for lava spike, some of the red decks that are basically all burn spells are considered to be kind of combo decks.
And as for spider spawning, yes it wins through attacking with creatures, but a lot of its game plan involves filling up its graveyard and leveraging that zone to its advantage, which isn't something most decks do. How you actually win isn't relevant. Storming into Goblin Warrens actually kills you through turning men sideways, but it's still definitely a combo deck.