Lots of Them. Our doubles of conventional bids, such as responses to Stayman or Blackwood, are lead directing.
N E S W
1NT P 2§ Dbl "East, lead Clubs" says West.
1NT P 2© Dbl "East, lead Hearts", says West.
Failure? Failure to double is also informative. If you don't double a Blackwood response, for example, your partner will assume you aren't particularly interested in a lead of that suit - he will not assume you are asleep.
1ª P 3ª P
4NT P 5¨ P
West isn't especially interested in a Diamond lead.
(c) Robert D. McConnell, 1998 All Rights Reserved