A list of factors of a binary word

Question

I want a list of ALL contiguous sub-sequences of a binary word w, say w={r,d,r,r,d}.
I have;
w = {r, d, r, r, r}; {Drop[w, 1], Drop[w, -1]} which gives the length 4 subsequences : {{d, r, r, d}, {r, d, r, r}}.
How do I get All of such sub-sequences?
That is I want: Input:={r,d,r,r,d}
Output:{ {r,d,r,r,d}, {d,r,r,d},{r,d,r,r},{r,r,d},{d,r,r},,{r,d,r},{r,d},{r,r},{d,r},{d},{r},{}}
(not necessarily in this order).

kglr · Accepted Answer

You can use Subsequences:
list = {r, d, r, r, d};

DeleteDuplicates @ Subsequences @ list

{{}, {r}, {d}, {r, d}, {d, r}, {r, r}, {r, d, r}, {d, r, r}, {r, r, d}, 
 {r, d, r, r},  {d, r, r, d}, {r, d, r, r, d}}

You can also use SequenceCases with the option Overlaps -> All:
Union @ SequenceCases[list, {___}, Overlaps -> All]

{{}, {d}, {r}, {d, r}, {r, d}, {r, r}, {d, r, r}, {r, d, r}, {r, r, d},
 {d, r, r, d}, {r, d, r, r}, {r, d, r, r, d}}

A list of factors of a binary word

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