List::Compare works for this problem:

use strict;
use warnings;
use List::Compare;

my @dbs = qw(fetch forward user smtp);
my @skip_dbs = qw(user smtp);

my $lc = List::Compare->new(\@dbs, \@skip_dbs);

my @list = $lc->get_unique;

print @list;
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Cheers,

Brent