DKIMwl.org is DNS based reputation service which is free for use* for all your DKIM verification needs.
Domains are added and voted on by our community of users. Scores are derived using Wilson score interval and other tools to produce a score and category for each DKIM signing domain.
At present we're classifying around 44.72% of signed DKIM emails globally.
Start querying the database now above, or configure you spam fighting product to use our DNS servers.