An openface one is available. It does not change size in superscripts.
Here is an example: $\openone$ gives 
.
\openone is a fragile command and must be immediately preceded by
\protect when used in section headings and captions.
Bold large bracketing is also available. The normal commands
\Biggl,\Bigl,
, when used with an extra ``b'' on the
end of the command, come out bold:
\[ \Biggl(\biggl(\Bigl(\bigl( (x) \bigr)\Bigr)\biggr)\Biggr) \]gives
while
\[ \Bigglb(\bigglb(\Biglb(\biglb( (x) \bigrb)\Bigrb)\biggrb)\Biggrb) \]gives
The commands \lesssim,\gtrsim give the output
, even without the amssymb style option.
(The commands \alt,\agt, respectively, may also be used.)
These commands will be fragile if you are not using the amssymb option.
Some extra diacritics have been provided. They scale correctly in
superscripts. Some examples follow.
$\tensor{x}$ gives 
.
$\overstar{x}$ gives 
.
$\overdots{x}$ gives 
.
$\overcirc{x}$ gives 
.
$\loarrow{x}$ gives 
.
$\roarrow{x}$ gives 
.
These commands all work correctly in superscripts.
\slantfrac{#1}{#2} produces a slanted fraction in math mode:
.
This command should not be used in files destined to be submitted to
the APS (normal upright fractions will be produced).
\corresponds produces the symbol 
math mode,
\precsim produces 
in math mode, and
\succsim produces 
in math mode. The AMSFonts will be used
for these symbols if you have them, but are not necessary.
\lambdabar produces ``lambda-bar'' in math mode: 
.