I recently visited Knoebels and made a stop in the Christmas Cottage where they sell Knoebels decorated O gauge trains. Back in 2018, only three cars were sold out. Currently, they have seven cars sold out including the 90th Anniversary car that started this thread. So much for the naysayers from five years ago!
To the best of my knowledge, here is the list of Knoebels train releases:
Year? Lionel 4-4-2 engine, tender and caboose
1995 Lionel Boxcar #1 (green) - sold out
1998 Lionel Boxcar #2 (red) - sold out
1999 Lionel Boxcar #3 (blue) -sold out
2000 Lionel Boxcar #4 (Phoenix)
2001 Lionel Boxcar #5 (75th Anniversary)
2007 Weaver Flat with Lumber (Flying Turns) - sold out
2011 Weaver 3 Bay Offset Hopper - sold out
2009 Weaver Woodside Reefer
2013 Weaver (MTH) Madison Passenger Car - sold out
2015 Weaver PS-1 Boxcar (Impulse)
2016 Lionel Boxcar (90th Anniversary) - sold out
2019 Lionel Unibody Tank
2020 Lionel Passenger Loading Platform
Feel free to update if anything is incorrect.
Also, those of us on the mailing list will be receiving a mailing for a new Lionel car that is already in stock!