My own oracular devices: stones and shells.
Actually, I keep the bits of shell and stone in an old spice jar to shake out the rhythms for the songs on the radio in my truck as I drive; yes, I'm that guy. The abalone pendant I wear fairly often; I found the piece of shell under a rock on the bottom of a favorite cove. Both the maraca-jar and the necklace help me to focus.
The passage I keep thinking about from Charles de Lint's fine urban fantasy novel Trader:
"I guess it all depends on how you look at it," Bones says. "Now me, I figure all oracular devices are just a way for us to focus on what we already know but can't quite grab on to. It works the same as a ritual does in a church -- you get enough people focused on something, things happen. The way I see it is, it doesn't much matter what the device is. It's just got to be interesting enough so that your attention doesn't stray. Fellow reading the fortune, fellow having it read --same difference. They've both got to be paying attention.
"What you get's not the future so much as what's inside a person, which," he adds, "is pretty much the real reason they come to you. They're trying to sort through all this conversation that's running through their heads, but they get distracted. Me, what I'm doing with my hands, with the bones, it forces them to pay strict attention to me. The noise in their heads quiets down a little and they can hear themselves for a change. It's my voice, but they're doing the talking."
"So will you read my fortune?" I ask.
Bones looks regretful, but shakes his head.
"Why not? Let me tell you, I could use someone to make a little sense out of what's going through my head."
"You don't believe."
"But you just told me that it's just a matter of paying attention. I can do that."
"It's not the same."