Since items can't be transferred to Generation 5, are there Generation 4 exclusive items?

Question

There have been items exclusive to Generation 2 (berserk gene), Generation 5 (gems), and Generation 6 (thankfully, loppunite is one of them). TMs, key items, and unobtainable items don't count. Please don't question my curiosity.

Comments

Does this include Key Items or not? I've looked and it doesn't seem that there are any items not available in later or previous games other than TMs and Key Items. Also the Pal Park Pokeball but w/e on that one.

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Okay I edited the question.

Answer 1

I've cross referenced lists from Serebii, Bulbapedia and Psypoke against each other and it seems that no usually obtainable items are unique to Generation 4 games. So no, is the short answer.

Also screw you Pal Park Pokeball