I believe that the more appropriate translation would be:
"There are three more to come"
though I wrote the answer they suggested.
I think you might be confusing "Sie stehen vor uns" with "Sie stehen uns bevor".
why is it not 'es steht'?
I think it's the same principle as "Das sind" for these/those are, the neutral pronoun becoming a plural one. Just an educated guess, mind you.