The most common and most likely answer to this crossword clue is the 8 letter word SAVIOURS
I've seen this crossword clue in The Guardian
S
A
V
I
O
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S
More clues leading to the result SAVIOURS
Buddy explains!

The straight part
We know that "rescuers/rescuers" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case rescuers/rescuers = saviours.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SAVIOURS mean?
SAVIOURS noun- A person who saves someone, rescues another from harm.
- A child who is born to provide an organ or cell transplant to a sibling who has an otherwise fatal disease (used in combination, with "sibling", "baby", "child", "brother", "sister", etc.)