There is no way to know how many concealed carry cert petitions have been denied by SCOTUS since the Heller decision was published back in 2008 short of having a boatload of money to hire a company to go through every cert petition filed since then.
The following cert petitions were filed by the so called gun-rights groups and denied in short order. The links open a new window at SCOTUSblog
Kachalsky v. Cacace Petition for certiorari denied on April 15, 2013
Woollard v. Gallagher Petition for certiorari denied on October 15, 2013
National Rifle Association of America v. McCraw Petition for certiorari denied on February 24, 2014
Drake v. Jerejian Petition for certiorari denied on May 5, 2014
And here are the SCOTUSblog pages for Heller, McDonald and Caetano. When the Caetano cert petition was granted it had been 6 years, 5 months, and 21 days since the last Second Amendment cert petition was granted in McDonald.
District of Columbia v. Heller – Petition for certiorari granted on November 20, 2007.
McDonald v. City of Chicago – Petition for certiorari granted on September 30, 2009.
Caetano v. Massachusetts – Petition for certiorari granted on March 21, 2016.