What evidence is there for other universes?
At the present time, nothing direct.
We have no evidence for the existence of any universe other than
the one we happen to live in. The existence of others is purely
speculation at this point.
However, the existence of other universes -- an almost infinite
number of them, most them completely hostile to intelligent life --
would answer the question of how this universe, that we happen to
live in, seems to be so well "balanced" so as to permit us to be
here. If there are, indeed, an infinite number of universes, then
it should be no surprise that at least one of them would allow
intelligence to develop within it. The other universes simply have
nobody getting upset that they can't exist there.