:There are still plenty of things to add/change.  The triple bar is far more commonly used to indicate material equivalence than to indicate definition (if it does the latter ever).  The equals sign is commonly used for strict equivalence.  Double turnstile is missing.  It should be noted that – is sometimes used as negation, and . is sometimes used as conjunction (but also periods are used to serve the same purpose as parentheses sometimes).  Then there are, of course, the modal operators including the box (necessary, obligatory) and the diamond (possible, permissible) and the fishhook (strict implication).  Philosophers also often use the set membership, intersection, and union symbols.  Also the slashed equals sign, turnstile, double turnstile and set membership symbols are used to indicate the negation of those relations.  Then if we really wanted to get crazy, we could include even rarer things like corner quotes or the substitutional quantifier.  (I'd fix most of this right now, but tables annoy me and I don't have the patience to figure this one out at the present moment.)