Books on historical and cultural context help you understand what is going on in and around the various Bible texts. They will give you information on what life was like for ancient Jews or what Greek philosophers were teaching at the time of Paul.
These dictionaries will provide explanations of words that appear in the Bible both in lexical meaning and any theological import attributed to them. In addition, geographical places, people, and other Biblical concepts are addressed.
Interlinears are useful for finding exactly what English words are behind the Hebrew and Greek languages in the Bible. Reverse-Interlinears provide English translations with the original languages beneath.
Exhaustive English concordances are often keyed to a specific translation of the Bible (i.e. NIV, NASB, KJV, etc.) and provide a list of every word found in that translation and where they appear.
Several other guides are useful for finding information on Bible topics.