Dave's Math Tables

Has math tables for many areas of math from general math to advanced calculus. Includes areas formulas and integral approximation formulas.
http://www.math2.org/

Some Useful Mathematical Tables

A collection of mathematical tables which, for some reason, have not been published elsewhere.
http://www.maths.soton.ac.uk/staff/Dewynne/mathtables.html

S.O.S. Math - Mathematical Tables and Formulas

Large integral tables along with other math tables. Polynomial, trigonometric, logarithmic, hyperbolic. and Laplace transform tables.
http://www.sosmath.com/tables/tables.html

Tables of Mathematical Constants

A list of known constants with a precision of 16 digits.
http://pi.lacim.uqam.ca/eng/table_en.html

A Million Random Digits with 100,000 Normal Deviates

Free online in PDF, also offered for sale as paperback. Notes on the data and instructions for accessing the files in either plain text or compressed format are provided.
http://www.rand.org/publications/MR/MR1418/index.html