My original source on that was TPPF. Marc Levin calculated it. First time I wrote about it was here:
Note that in the comments someone actually named a bunch of them. See also this somewhat satirical followup:
There are also, of course, oyster related misdemeanors, see:
It should be mentioned that the way the code is written it's VERY difficult to count crimes because it's hard to know whether to count each enhancement as a separate crime and there's inevitably a lot of interpretation. Notably, nobody actually knows how many federal crimes exists - there are several estimates, each of which have been disputed.
The parole board after each session updates the list of crimes in its "Offense severity list" which is the count I tend to rely on. They have to identify each individual crime in order to classify it for risk categorization purposes. See the most recent one at:
I'd suggest searching on the word "oyster" and counting them.