There is basically three (somewhat overlapping) lists of Q-codes used in Ham Radio. The three lists are those used by voice operators (SSB), those used by CW operators, and those used in CW traffic handling nets (QN codes).
A full single "official" list of Q-codes is not useful to the ham radio operator. What is useful is to know those that are commonly used. The use of Q-codes is most dominant among CW operators because CW begs the use of abbreviations to limit keying. Use of Q-codes among voice operators, mostly SSB is also common but the usage is typically more limited to just a handful such as: QSL, QSO, QSB, QRM, QRN, QTH, QSY, QRZ, QRL, QRU, and maybe a few others I am missing. But, many times a voice operator will merely say something equivalent to the Q-code meaning. For example, he/she might say "I am being interfered with" instead of "there is QRM" or "there seems to be a slow fade on your signal" rather than saying "some QSB on your signal". Note that I am listing these as I think of them and obviously the same set is not the common usage of all operators. But, you can expect to hear these at times among SSB operators. [By the way, many SSB voice operators would say "QR-Mary instead of QRM or QR-Nancy instead of QRN (atmospherics noise or other non-operator RFI)].
With CW operators, you can add to the list signals (above) such as QRT, QRV, QSP, QRS (and, less frequently QRQ), QST (by scheduled nets usually).
And, within a CW traffic net, the QN signals are common such as: QNI, QNX, QNZ, QNA, QNZ, QND, and a few others.
When asking a question via a Q-code in CW it is common practice to include a ?-mark following the Q-code. For example, a CW operator will check to see if his frequency is clear by sending QRL? meaning "is the frequency busy?". An answer of the letter C from someone if the answer is yes, it is busy. The letter C is a common CW abbreviation meaning Yes.
Now, in the above lists I did not define these Q-codes because they are very easy to look up. The ARRL has lists published on their web site plus these Q codes and many more are published on many web sites. Just Google "Q signals ham radio" or some variation of that and you will find them.
Also above, I did not list every Q-code known to amateur radio. Some are never heard. I am almost 100 percent CW activity and I spend a lot of time on CW traffic nets and I use maybe a dozen total Q codes from the regular Q code lists and the QN codes.