Tables

Research Information - Larry Lehman - Includes a list of publications with abstracts, and tables of elliptic curves of small rank and various conductors.
http://people.umw.edu/~llehman/research.htm

Mordell Curves - Minimal known positive and negative k for Mordell curves (y^2=x^3+k) of given rank, by Tom Womack.
http://www.tom.womack.net/maths/mordellc.htm

Elliptic Curves with Unusual Torsion - Two tables: the smallest conductor observed for a given rank and torsion, and the smallest conductor observed among curves of rank zero with a given Sha and torsion. Maintained by Tom Womack.
http://tom.womack.net/maths/torsion.htm

Elliptic Curve Data - Tables of elliptic curves of small conductor in Mathematica format.
http://library.wolfram.com/infocenter/Demos/154/

Rational Points on Elliptic Curves - A wide collection of known integer solutions to elliptic curves and their corresponding Diophantine equations, presented by Hisanori Mishima.
http://www.asahi-net.or.jp/~KC2H-MSM/ec/eca1/index.htm

Iwasawa Invariants of Elliptic Curves - For each curve (labelled as in Cremona) the mu and lambda-invariants are listed for the primes between 2 and 17. By Robert Pollack.
http://math.bu.edu/people/rpollack/Data/data.html

Siegel Forms - Coefficients of some Siegel automorphic forms, by Richard Borcherds.
http://math.berkeley.edu/~reb/papers/siegel/

Class Polynomials of CM-fields - Class polynomials of the principal orders up to discriminant -300000, giving values of the Weber invariants. By Annegret Weng.
http://www.exp-math.uni-essen.de/zahlentheorie/classpol/class.html

MODI - Interactive Modular Forms Data Base - Data about modular forms which are computed on demand or taken from a data base of precomputed items, maintained by Nils-Peter Skoruppa.
http://wotan.algebra.math.uni-siegen.de/~modi/

Drinfeld Modules - Complete tables of sign-normalized, rank one, Drinfeld modules on the elliptic curves over finite fields of order less than 16.
http://www.math.umass.edu/~dhayes/dmods.html

Deformations of Maass Forms - Tabulated by Stefan Lemurell.
http://www.math.chalmers.se/~sj/Maass/

Modular Forms Database - Tables computed by William Stein using HECKE, LiDIA, PARI and Magma.
http://modular.fas.harvard.edu/Tables/

Elliptic Curves with Complex Multiplication - Defined over extensions of type (2,...,2). Tables by Joan-C. Lario.
http://www-ma2.upc.edu/~lario/ellipticm.htm

Mordell Curves - Data on the elliptic curves Y^2 = X^3+k for |k|<10,000.
http://tnt.math.metro-u.ac.jp/simath/MORDELL/

Modular Polynomials - Tables and Maple software for modular polynomials of composite level by Masanari Kida.
http://matha.e-one.uec.ac.jp/~kida/modularpoly.html

Best Known Conductors for Elliptic Curves of Given Rank - Up to rank 9, by Tom Womack.
http://tom.womack.net/maths/conductors.htm

Classical Modular Polynomials - Tables of modular polynomials Phi_l for prime l to 270, computed by Michael Rubinstein. Gzipped text and specially compressed formats.
http://www.math.uwaterloo.ca/~mrubinst/modularpolynomials/phi_l.html

Infinite Families of Elliptic Curves with Prescribed Torsion - Compiled by Andrej Dujella.
http://www.math.hr/~duje/tors/generic.html

High Rank Elliptic Curves with Prescribed Torsion - The highest rank currently known for an elliptic curve over Q with each of the possible torsion groups. Compiled by Andrej Dujella.
http://www.math.hr/~duje/tors/tors.html