The first ones that popped into my head were Aussie Floyd, The Fab Faux, and The Musical Box. Some might debate whether or not the Fab Faux is truly a tribute band because they are primarily focused on recreating the songs rather than going into character, replicating a stage show, etc., which is something The Musical Box has exceled at (though I don't think they're quite as good a show as they were in their first 10-15 years or so). But The Fab Faux are a DANG good show!
Of those three, I'd say that Aussie Floyd probably grosses the highest from their shows based on the sizes of venues I've seen them play in.
I always, somewhat jokingly, said that Heart could have been the world's best Led Zeppelin tribute band. They're huge fans of Zep to begin with and every time I've seen them them live in the past 20 years they've done at least a few Zep songs and absolutely nailed them.