20 Raka’at of Taraweeh in the Hambali school of Fiqh
Allama Ibn Qudama Hambali (May Allah shower His mercy on him) writes in his book Al Kafi:
فالسنة أن يصلي بهم عشرين ركعة في الجماعة لذلك ، ويوتر الإمام بهم بثلاث ركعات -
Translation: It is a Sunnah that Taraweeh should be offered as congregational prayer of 20 Raka’at and the Imam should lead the people in Witr also.
(Al Kafi, Kitab Us Salaat)