Here is a list of books and other reference works on the Hebrew Bible that I've found interesting or useful. I may add to it from time to time.
A high-quality online text of the Hebrew Bible, matching the Leningrad Codex, can be found online at tanach.us.
For those still learning Hebrew, one useful tool is the Bible Online Learner program, from the Eep Talstra Center for Bible and Computer. It allows the reader to hover the mouse over any word in the Hebrew Bible, or New Testament, in order to quickly "look up" its meaning and grammatical details.
Gesenius, Hebrew Grammar. Can be found on Wikisource, here.
Gesenius, Hebrew and Chaldee Lexicon. A page-by-page scanned edition, navigated by frames, can be found at the Tyndale Archive. A more traditional facsimile version, this time of the translation by Tregelles, can be found at archive.org.
BDB, or Brown-Driver-Briggs, A Hebrew and English Lexicon of the Old Testament. Can be found at archive.org here.
DCH. Cline's Dictionary of Classical Hebrew.
HALOT. The Hebrew and Aramaic Lexicon of the Old Testament.
Joüon and Muraoka, A Grammar of Biblical Hebrew.
Ewald, Syntax of the Hebrew Language. 1891, translated from the eighth German edition by James Kennedy, B. D.