In United Housing v Foreman, a sale of stock was considered not to be a securities transaction, even though a stock is explicitly a security.
You might find SEC v Lauer[1] interesting. Where a non-existent hypothetical investment was determined to be a security. As well as SEC v Edwards[2], where a fixed-rate leaseback agreement for payphones was determined to be a security.
[1] https://caselaw.findlaw.com/us-7th-circuit/1054989.html
[2] https://caselaw.findlaw.com/us-11th-circuit/1156201.html
I think my main point was that if Howey had 100 fungible orange groves, and one was sold as a security and 99 were sold straight up, that wouldn't make all 100 orange groves as a security, would it?