Playbooks

Seattle out of Singleback Bunch is a play-action flood concept built to attack one side of the field with three vertical levels. The bunch receivers release into a corner route, a deep go up the seam, and an out breaking flat route underneath, while the backside X runs a deep post to hold the safety, and the play-action fake from the blue running back path sells the run to slow the linebackers. It is a Cover 2 and Cover 3 beater that overloads the flat to deep corner zones, with the primary read progressing from the flat route underneath, up to the corner, and finally to the go route if the cornerback bites on the shorter stuff.
Identify single high safety alignment pre-snap, since Cover 3 leaves the corner route defender in conflict between the deep third and the flat route running underneath. Watch the cornerback over the bunch, if he sinks with the go route the flat and corner routes will be wide open behind him. Key the flat defender post-snap, if a linebacker or nickel jumps the underneath flat route immediately, the corner route window opens up for a bigger gain. This play struggles against a hard Cover 2 with the corner staying high and a linebacker spying the flat, since both underneath and intermediate throws get taken away. Beware a user controlled safety rotating late to double the corner route, which can turn a flood concept into a turnover if you force the throw.
Check pre-snap for two high safeties versus one high, since this flood concept is designed to stress Cover 2 corners who have to choose between the flat and the corner route.
Use the play-action fake fully by letting the running back animation play out, this holds linebackers and opens passing lanes for the intermediate flat route.
Hot route the backside post into a shorter option like a curl if you are facing heavy Cover 3 zone drops and need a quicker outlet against a four man rush.
Pair this with Sluggo Seam or PA Cross Switch earlier in a series so the defense has to respect both the deep shots and the underneath flood concept from the same bunch look.
Best called on second and medium to third and long situations where defenders are more likely to sit in zone coverage and give up the flat to corner combo.