Topband: Beacons, Digis, & Other Band Indicators?

[Jeff Maass]

Does anyone have a list of stations that can be 
listened-for that indicate the band conditions
to various areas of the world?

I've heard mention of some of these ("ZL Digis"(?),
for example) in individual references, but have
not seen a list of them together.

If no one has a list already, maybe we can compile
one here? What reliably-on-air signals do you
listen for to give clues as to topband conditions?

73,

Jeff Maass  K8ND