One of the great things about the modern Allen & Ginter release are the scarce inserts that are considered 1 of 1 cards. Personally, I've never pulled anything that rare in all of my years of breaking open packs, but that doesn't keep me from trying. Yes, Baseball cards is a lot like playing the lottery.
Since I doubt I will ever, by chance, pull one of these I figured the best I could do is search them out and post some of the rarities here. First, each card in the set has mini printing plates inserted for each player. Below is Matt Kemp's yellow printing plate. It recently sold for a seemingly tame $36.65 on eBay. Another one is on eBay- this time the cyan printing plate.
Each mini card in the set also has silk reproductions. Now, these are not "1 of 1's", but are limited to only 10 each. Below is a Jonathan Broxton silk card. Also, wooden reproductions are also available for each mini card, but I have yet to see a Dodger pop up.
Now here are the real doozies. Allen & Ginter has included "1 of 1" DNA/Hair relic cards in packs, and some of them have already been pulled. Below is Jacqueline Kennedy Onassis with a high price tag of $7,999.99 on eBay.
Or how about a strand of hair from good ol' Abe Lincoln.The coolest "1 of 1" to show up is clearly this jumbo box topper nameplate card. It is a rather large piece of one of Tony Hawk's skateboards. It recently sold on eBay at $700.67.