I dont have the 2010 yet, but in the 2009 there are a couple I can think of. (I dont have the guide with me right now)
Price listed is way off
1925 Holland Ice Cream #16 Peckinpaugh card (chase card)
There is only a single known example and it sold 1 time as far as I know of..... I sold it about 8 years ago (privately) for $3K in G/VG yet the catalog still has it listed at $2500 NRMT. IMO it should be listed at roughly $10K NRMT, $5K EX, $3K VG, if not more (it is similar to the 1923 Maple Crispettes #15 Stengel card).
scan of card
Error
the 1920 W519 numbered type 2 (aka W519-2-2)
There are 3 cards listed as "b" variations (12b, 13b, 20b) that Im 99.997% sure are really misidentified W521's.
W519-2-2 have light blue numbers, W521 have black numbers.
Update
W517-2 mini's, the complete set is only 16 cards, not 54 like the normal W517's.
W517 Mini's Checklist (Cochrane, Collins, Critz, Donahue, Gehrig, Grove, Jackson, Judge, Kamm, Kelly, Klein, Miller, O'Doul, Shire, Vance, P.Waner)