Drew Brees and Y.A. Tittle, among others, congratulate Manning on record

This was done via pre-recorded message.

Here is Y.A. Tittle:

LINK

Here is Drew Brees:

LINK

There were individual videos for each person and then one large video including all of the congratulation messages. Here is that large video. The people congratulating Manning are Elway, Tom Brady, Aaron Rodgers, Dan Marino, Drew Brees, Y.A. Tittle, Fran Tarkenton, Sonny Jurgenson, Brandon Stokley, Jeff Saturday, and of course Brett Favre.

LINK

They are gracious, but Brees was far and away the most complimentary among active QB's. Tarkenton straight up called him the GOAT.

ETA: fixed last link to correct video