Yea, but you can't really tell if the RNG of a computer game is acting weird either because how its RNG'ing those numbers is hidden. It also probably isn't behaving as the definition for random you want. Most RNG's tend to be weighted.
And humans are also pretty terrible at being able to recognize what is random. Random doens't look like how we intuitively want random to look like.
Anyway...
For OP question.
There are plenty of dice rolling engine out there that can show ya. Though you can do it be hand, in a very tedious fashion.
So the number of combination that any group of dice can make, is 6 to the power of number dice rolled.
So for two d6 (6^2), the the total number of combination is 36. There are 36 different combinations that two d6s can make, with a range of 2-12 for their total.
And then you can work out the 2d6 bell graph yourself pretty easily. Get a piece of paper, and then we're gonna make a bar graph. List the bottom the values between 2 through 12. And then record how many dice combination make those values.
So for 2, there is only one combination of the 2d6 that make 2. Snake Eyes. Then for 3, there is two combination of dice that make 3. One pip and Two Pip, and Two Pip, and One Pip. And for 4 there are three different combination that total 4. One Pip, Three Pip. Three Pip , One Pip. Two Pip, Two Pip.
So on and so forth.
And this bar graph will illustrate the bell curve of the probability of 2d6. Just draw a snakey line over the top of the bars. It'll make a rough bell shape.