Gnomes

The 15-year pass-through securities offered under Freddie Mac's cash program.

Investopedia Says:
Investors sell their mortgages through Freddie Mac's cash program. The 15-year mortgages sold to Freddie Mac form the pool of mortgages that back the securities referred to as gnomes.

Popular name for 15-year fixed rate Participation Certificates sold by the Federal Home Loan Mortgage Corporation (Freddie Mac). Gnomes are Pass-Through Securities collateralized by mortgage payments from 15-year mortgages.