Which mousebutton is held down/pressed?

Is there any better way of checking which mouseButton is pressed other than:

if (Input.GetMouseButtonDown(0))
   held = 0;
else if (Input.GetMouseButtonDown(1))
   held = 1;
...

Input.GetMouseButton

It doesn’t return the actual id of the mouseButton

Sorry i read your question wrong.
I guess you could go for a for loop

for(int i = 0; i < *number of mouse buttons*; i++){
    if(Input.GetMouseButtonDown(i)){
        held = i;
    }
}

What do you want to happen if both mouse buttons are held down?

Well, if it’s possible to get an array/list of these, that would be perfect, but I would prioratize the one with smaller id