Activate Woe Strider by sacrificing Wingrattle Scarecrow
When Wingrattle Scarecrow dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
When Wingrattle Scarecrow enters, Serra Redeemer triggers, putting a +1/+1 counter on Wingrattle Scarecrow
Resolve the Woe Strider ability.
Repeat.
This clever loop turns Woe Strider into a sacrificial engine that continuously recycles Wingrattle Scarecrow. Every time the Scarecrow perishes, its persist ability brings it back with a -1/-1 counter, which is immediately nullified and countered by the two +1/+1 counters granted by Serra Redeemer's triggered ability as the Scarecrow re-enters the battlefield with a power of 2 or less. This endless cycle not only lets you manipulate your library at will through Woe Strider's scry ability, but also generates an unstoppable wave of artifact and creature triggers to overwhelm your opponents.