Couldn't find any tools out there aside from ksd which is great in a case where you need to look at individual secrets, but doesn't work if you are looking through many secrets.
Instead, I managed to find a way to do this in a bash shell instead:
# get all secrets
kubectl get secrets -o json --all-namespaces > /tmp/all.json
# use jq to look through and dump all the cleartext secret values: