English sets since.... a long time ago (i can't remember the specific set lol!) have, in addition to the normal cards in the series, included a "Reverse Holofoil" set.
All sets include Rare (and Ultra Rare) Holographics ("Holos", including EXs and Shining pokemon), non-holographic rares, non-holographic uncommons and non-holographic commons. A reverse holofoil set essentially turns everything in the set into a holofoil, with most sets having their own specific holofoil design. Non holo Rares, Uncommons and Commons are given a holofoil treatment, and Holo Rares are given a different holofoil treatment to the one they already have.The EXCEPTION here is ultra rares holographics- EX's and shinings are thus NOT part of a RH set.
How to tell the difference between a Holo rare and a Reverse foil-Holo Rare--> well, that largely depends on the specific reverse holofoil treatment design for the set. Most of the time- a Holofoil rare's picture part of the card is the only part that is given the treatment, whereas its reverse holo equivalent is given the treatment in its entirety- the whole card is "shiny".
I hope that's helped answer your question! Anyone, feel free to help me out- that was only off the top of my head!
