Answer by jthill for How do I recover a dropped stash in Git?

tl;dr: much faster than the fsck method, so, helpful on long histories, is:

find .git/objects/?? -type f -exec ls -t {} + | awk -F/ '{print $3$4}' \| git cat-file --batch-check | awk '$2=="commit" { print $1 }' \| git log --no-walk --stdin --merges

or you've set your clone for really frequent automatic compaction, or just got unlucky and went looking that soon after a repack, this is still a good bit faster than fsck'ing:

{ find .git/objects/?? -type f -exec ls -t {} + | awk -F/ '{print $3$4}';  git verify-pack -v $(ls -t .git/objects/pack/*.idx) | awk '$2=="commit" {print $1}';} | git cat-file --batch-check | awk '$2=="commit" { print $1 }' \| git log --no-walk --stdin --merges

and with the default stash messages you can add --grep '^WIP' to the final git log options.

The breakdown on the above commands is:

Recently-added objects, most-recent first, with type and size appended

find .git/objects/?? -type f -exec ls -t {} + | awk -F/ '{print $3$4}' \| git cat-file --batch-check

Recently-added merge commits, most recent first:

find .git/objects/?? -type f -exec ls -t {} + | awk -F/ '{print $3$4} \| git cat-file --batch-check | awk '$2=="commit" { print $1 }' \| git log --no-walk --stdin --merges

If Git is set to very aggressively pack up loose objects (by default it doesn't bother until there are clearly gratifying compression wins available) the above find can be unreliable; to avoid having to search all the packed history for candidates you can extend your search to include the most-recently-packed objects with

git verify-pack -v $(ls -t .git/objects/pack/*.idx|sed q) | awk '$2=="commit" {print $1}'

and folding that in to the find above gets

{ find .git/objects/?? -type f -exec ls -t {} + | awk -F/ '{print $3$4}';  git verify-pack -v $(ls -t .git/objects/pack/*.idx) | awk '$2=="commit" {print $1}';} | git cat-file --batch-check | awk '$2=="commit" { print $1 }' \| git log --no-walk --stdin --merges