My partner found the Bulbasaur Mega Construx for half price and, on building it, we discovered it has an unorthodox pin where a not-Lego brick works as the pin back. Not sure it’s within your scope, but in case you haven’t already seen it:
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I just came across your thread for the first time, and I’m truly impressed by your stunning collection and dedication. Thank you for sharing these fascinating pieces!
Your latest find looks particularly special and highlights the diverse range of items you seek out. 
Looking forward for more updates. 
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Looking at other Mega Construx sets on ebay, a lot of them also have an exclusive pin. Very interesting, thanks for sharing!
I knew about a similar promo pin from SDCC 2023 but I never could wrap my head around why it was called a “pin”
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Got these pins from working at Pokemon Go Fest NYC the last 2 years the 2023 one i was the judge for the battle grounds that year giving them away to winners. The 2024 pin was given to me by a co-worker, and the necrozma pin was a preorder from that year that a friend who also went gave to me
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