I think I can see five cables. Do they all go into that junction box?
Really, you are going to have to get an electrician to test which, if any, are live, and where they go. Wall lights or cabinet lights would be the least worrying, but unusual to have so many cables. Is it in a place where a hifi system or TV might have been? Or display cabinets? Are there any switches nearby that don't seem to do anything?
out of interest, see what size they are. A good way is to go to the hardware or DIY store and buy the smallest possible pack of cable clips (probably a dozen or so in a plastic bag, like they sell screws). The most popular sizes in a house are 2.5mm T&E and 1.5mm T&E. Occasionally you see 1mm, and there are some different sizes for particular puposes. 1.5mm is generally used for lights, and 2.5mm is generally used for sockets. This might give some useful clues to what they were for, and if they are ut of the ordinary.
The "sizes" of clips do not relate to the size of the cable outer, or the diameter of the cores; it is the cross-sectional area of the copper within each core, so this is much easier that trying to measure them. The correct size clip will clip tightly onto the cable sheath, and pop off if twisted.
sample Observe that it is rectangular, not round.