How rare is a holon charizard Pokemon card?

Its the ancient mew holofoil promo card u could get it at pokecorner.com

Yes and no. Some people say it is rare, others don't, but in true fact it is as rare as Articuno or Zapdos or Mewtwo and so on and so forth.

No they are not. I have been collecting Pokemon cards for almost my whole life and majority of the cards are trainer cards.

Not necessarily. You get at least one foil card in every pack, and many promotional sets will have a shiny card in. Some cards are both rare and in foil, but foilness alone doesn't imply rarity.