I have a multitude of resources online. Below is a list of resources that I have found helpful over the years. This list is a starting point, and not intended to present an exhaustive list of resources.
Commentary — Biblical commentaries are written by individual scholars or a group of scholars. Sections of Scripture are systematically explained. Explanations will include information on culture norms, original language, and cross reference other passages. Of course it is important to use commentaries by respected scholars. A quick way to judge the quality is to look up a passage you absolutely know the meaning of and compare what you find in the commentary.
Matthew Henry’s Biblical Commentary is widely used, but is considered a “devotional commentary.” Regardless of its devotional focus, I find it informative and refreshing. www.biblestudytools.com/commentaries/matthew-henry-complete/
A more modern, yet respected, commentary is the IVP Commentary (InterVarsity Press). The complete set contains one volume per book of the Bible. I was surprised to find the complete IVP New Testament Commentary online. www.biblegateway.com/resources/ivp-nt/toc/. This is a great tool.
Again Commentaries are oriented around specific passages and not topics.
Concordance – A Biblical Concordance is a true labor of love, and God bless the men who originally undertook this task, monks probably.
Some study Bibles will contain smaller concordances at the back. Concordances work off the “words” in Scripture. For example, if you wanted to examine Scriptures where Christ specifically taught about “money” you would look up the word “money” in the concordance. There you would find a listing of where the word “money” appears, with the book, chapter and verse reference for each occurrence in Scripture.
Concordances are also particularly helpful if you remember part of a verse, but cannot remember the location of it in Scripture. As well as when you want to compare what different sections of the Bible say about the same thing.
Concordances are crafted for specific translations. For example if you are researching “love” using a concordance for the King James Version, you will not find the famous 1 Corinthians 13:4-8 “Love is patient, love is …” passage listed under “love,” because in the KJV, 1 Corinthians 13 passage “love” is translated as “charity.” Bear this in mind when selecting a translation.
Topical Index – Biblical Indexes will also give you chapter and verse but are organized by topic. In our example about “money” a topical index would help you learn more contextual information about money. Information based on the culture and customs at a specific time in history. It may also include modern equivalences of money mentioned in the Bible.
Online Biblical Tools
Below are some resources online that might assist you in your research:
This is a great tool! One of my professors at Vangard introducted it to me years ago, and I love it. It is not as sophisticated as some tools out there, but it is free. There are versions for all software platforms, and a remarkable app.
You begin by downloading and installing the eSword framework, and then add on “modules.” You can download modules that include different Biblical translations. There are also options for downloading commentaries and dictionaries. Most of them are free, but newer translations, such as the New King James is available for a cost. You might find the online training pages helpful. www.e-sword.net/training.html
It is super integrated with cross references and commentaries all within a simple touch. The portability makes this one of my favorite tools. I have it installed on all my computers and my phone. So if you see me on my phone in church, I might be checking the original language of a word in the readings 
MOVE THIS ONE TO THE TOP – IT IS MY FAVORITE, This is a more in depth focus on the origins of Biblical words in their original language. Not as much “integration” as the above resource but still helpful. iOS based downloads available.
Clean, easy to use.
This site has everything; commentary, indexes, dictionaries, maps, concordances … interface is a little dated, but the information is good.