I'm trying to transfer assets from my account at Fidelity via ACATS but can't find that broker on your dropdown list.

Overview: 

Fidelity Investments uses its National Financial Services affiliate for certain clearing, custody and brokerage services including ACATS transfers.  To initiate a full or partial ACATS transfer from a Fidelity account, select  National Financial Services (DTCC No 0226) from the drop-down broker list.