A series of useful links recommended by Bob Nelson.
CALEB — Catalogue and Atlas of Eclipsing Binaries — very nice site with data, light and RV curves, Binary Maker images, etc.
Crakow Eclipsing Binary Database — data and O-C diagrams for some 3800+ EBs
Eclipsing Binaries Minima Database — times of minima only for numerous EBs (mostly BBSAG visuals, not always up-to-date)
Eclipsing Binary O-C Files — the author’s site, which contains some 1600+ Excel files with up-to-date times of minima
Henden Magnitude Sequence — standard magnitudes for areas around selected EBs
RHO — EB Ephemeris Generator — provides a list of possible eclipsers for your site on a given night
ROTSE — Robotic Optical Transient Search Experiment
2MASS DS Query Form — big complicated site enabling you to download data somehow
ESO Online Digitized Sky Survey — provides FITS images for any area of sky
GCVS — General Catalogue of Variable Stars
SOFA — Standard Objects for Astronomy (photometric standards)
TASS — The Amateur Sky Survey (confusing site)
W UMa — LC Solutions — List of authors with links to SIMBAD