Most people just say
which just means "excuse me" or "sorry". Sometimes you hear just the colloquial shortened version
which sometimes gets condensed to even more unintelligible versions (like »schuign«) (without changing its meaning). I guess that this shortened versions are different from region to region. My examples are form Austria. Maybe you will hear different versions in Germany, especially in the north.
Also in use is
Darf ich mal?
which is "may I", and you often find it combined with »Entschuldigung«:
Entschuldigung, darf ich mal?
and even longer:
Entschuldigung, darf ich mal durch?
(Excuse my, may I pass through?)
If waiters in a crowed area are carrying beverages or food, you also can hear
which means "attention". But normally you say »Vorsicht« only when you carry something that might hurt other people or could make them dirty if they touch it. You normally don't say it when you just try to pass trough a crowd.