How to find examples of best cases for sorting algorithms?
Bubble sort can "stop early" should the array already be sorted. Other algorithms have their own advantages or applications, but none of the algorithms mentioned in your question - other than bubble sort - can "stop early". 

Therefore for any input Insertion &amp; Selection runtime will be $\Omega (n^2) $, and Mergesort $\Omega(nlog(n))$, so the order of elements doesn't matter at all.

$\bullet $ If you perform bubble sort on an already sorted array, the algorithm can stop when not performing any swaps, and run at $O(n)$

$\bullet $ Merge sort (to which you refer as 'fusion sort' from some reason) is the only algorithm that requires $O(nlog(n))$ rather than $O(n^2)$

$\bullet $ Insertion sort is useful when receiving the array online (one element at a time) and maintaining it sorted. Its noteworthy that since you maintain a sorted array, new elements can be inserted via binary search, which make the insertion sort perform $O(nlog(n))$ comparisons, but still cost $O(n^2)$ due to moving elements.

$\bullet $ Selection sort is very easy to implement and intuitive to explain