The Draco has Thrust Reverse because the real model comes with that already set up from the factory. In real life, you can add thrust reverse to any plane using an ESC with that capability, including Spektrum's Avian Smart ESC's.
It looks like it's possible to add a thrust reverser to other planes in RealFlight in the same manner as they did on the Draco. You'd have to edit the Electronics on the airplane and add all of the things they added to the Draco. That appears to include a radio output channel (on the Radio tab), a servo, a mixer, and a modifier.