I donated employee stock units (@broker-1) to donor advisor fund account (broker-2). I know cost/sell basis, acquire/sell-date, etc. What tax form I need from brokers?

[DavidD66]

You need a letter from the donor advised fund.  Here are the IRS rules for cash or property donations: 

For any contribution of $250 or more (including contributions of cash or property), you must obtain and keep in your records a contemporaneous written acknowledgment from the qualified organization indicating the amount of the cash and a description of any property other than cash contributed. The acknowledgment must say whether the organization provided any goods or services in exchange for the gift and, if so, must provide a description and a good faith estimate of the value of those goods or services. One document from the qualified organization may satisfy both the written communication requirement for monetary gifts and the contemporaneous written acknowledgment requirement for all contributions of $250 or more.