Current list of spy pixels named'n'shamed in HEY, as of April 23, 2020

tracker_blocking.rb

module Entry::TrackerBlocking
  extend ActiveSupport::Concern

  included do
    has_many :blocked_trackers
  end

  email_service_blockers = {
    "ActiveCampaign" =>  /lt\.php(.*)?l\=open/,
    "AWeber" => "openrate.aweber.com",
    "Bananatag" => "bl-1.com",
    "Boomerang" => "mailstat.us/tr",
    "Campaign Monitor" => /cmail(\d+)\.com\/t\//,
    "Cirrus Insight" => "tracking.cirrusinsight.com",
    "Close" => "close.com/email_opened",
    "Constant Contact" => "rs6.net/on.jsp",
    "ContactMonkey" => "contactmonkey.com/api/v1/tracker",
    "ConvertKit" => "convertkit-mail.com/o",
    "Critical Impact" => "portal.criticalimpact.com/c2/",
    "Emarsys" => "emarsys.com/e2t/o/",
    "Gem" => "zen.sr/o",
    "Getnotify" => "email81.com/case",
    "GetResponse" => "getresponse.com/open.html",
    "GrowthDot" => "growthdot.com/api/mail-tracking",
    "FreshMail" => /\/o\/(\w){10,}\/(\w){10,}/,
    "Front" => /app\.frontapp\.com\/(.*)?\/seen/,
    "Hubspot" => /t\.(hubspotemail|hubspotfree|signaux|senal|sidekickopen|sigopn)/,
    "iContact" => "click.icptrack.com/icp",
    "Intercom" => [ "via.intercom.io/o", "intercom-mail.com/via/o" ],
    "Litmus" => "emltrk.com",
    "Mailchimp" => "list-manage.com/track",
    "Mailgun" => /email\.(mailgun|mg)(.*)?\/o/,
    "Mailjet" => "mjt.lu/oo",
    "Mailspring" => "getmailspring.com/open",
    "MailTrack" => [ "mailtrack.io/trace", "mltrk.io/pixel" ],
    "Mandrill" => "mandrillapp.com/track",
    "Marketo" => "resources.marketo.com/trk",
    "MixMax" => /(email|track)\.mixmax\.com/,
    "Mixpanel" => "api.mixpanel.com/track",
    "NetHunt" => /nethunt\.co(.*)?\/pixel\.gif/,
    "Newton" => "tr.cloudmagic.com",
    "Outreach" => "api/mailings/opened",
    "phpList" => "phplist.com/lists/ut.php",
    "Polymail" => "polymail.io",
    "Postmark" => "pstmrk.it/open",
    "Return Path" => "returnpath.net/pixel.gif",
    "Sailthru" => "sailthru.com/trk",
    "Salesforce" => "nova.collect.igodigital.com",
    "SendGrid" => "wf/open?upn",
    "Sendy" => "/sendy/t/",
    "Streak" => "mailfoogae.appspot.com",
    "Superhuman" => "r.superhuman.com",
    "Thunderhead" => "na5.thunderhead.com",
    "Tinyletter" => /tinyletterapp\.com.*?open\.gif/,
    "YAMM" => "yamm-track.appspot",
    "Yesware" => "t.yesware.com",
    "Zendesk Sell" => "futuresimple.com/api/v1/sprite.png"
  }.collect { |service, pattern| EmailServicePixel.new(service, pattern) }

  specialized_blockers = [ LitmusCssPixelBlocker.new, GmassPixelBlocker.new ]

  # Need to make sure GenericSmallPixel is always the last one on the list. Otherwise, it could catch pixels for some
  # of the services we're explicitly tracking.
  TRACKING_BLOCKERS = email_service_blockers + specialized_blockers + [ GenericSmallPixel.new ]
end

I've moved Simplify's tracker list from gist to an actual repo here: https://github.com/leggett/simplify-trackers

Has anyone seen this pixel at the end of a URL? +trackingPixel+

I haven't.