The Long Ashley Bend
This bend was described by Frank Michell in September of 2002.  It's a modification of the Ashley Bend that keeps the most heavily loaded portions of the rope in a gentle curvature in hopes of retaining maximum strength. 

The general concept can be extended to many symmetric
bends, but appears to be especially well-suited for this bend, because it usually proves difficult to make it jam, unlike other common low-initial-curvature bends.

If you're going to overload a rope
*, and you want to squeeze the last bit of strength out of the bend while still being able to untie it, you might give the Long Ashley Bend a try.

The intial positions might be hard to remember for beginners, so remember that after you make the "b" loop, bring the other rope end through the "b" from
below.  Then make your "q".  Note that both ends of the "b" and "q" are under the standing parts, unlike the super-symmetric Zeppelin Bend.  To tighten evenly, grasp the two free ends in one hand and the two standing parts in your other hand and pull.  I won't go into detail, but it's not too hard to imagine how to tie a Double or Triple Long Ashley Bend if you wanted to.
*Never exceed the safe working load of any rope if the job is at all critical.