... that I'm aware of ... were the two below. (of course we all know the Atomic Bombs had the bigger bang)
The Tallboy was a 12,000 lb bomb
Per Wiki: The T-10 was an American-made version of the 12,000 pounds (5,400 kg) Tallboy modified to use standard American components. Development was started in late 1944 and plans were made to drop them on the fortified island strongholds of the Pacific to aid in softening their defenses before amphibious assaults. None were ever used in combat, since the capitulation of Japan following the atomic bombings of Hiroshima and Nagasaki negated their need. In the late 1950s the T-10 was re-designated the M-121. During the Korean War a number of T-10s were converted to the radio guided Tarzon bomb and were used to destroy railroad bridges and reservoir dams, being dropped by the Boeing B-29 Superfortress.
The Grand Slam was a 22,000 lb bomb
Per Wiki: Beginning in March 1946, Project Ruby was a joint, Anglo–American project to investigate the use of penetration bombs against heavily–protected, concrete targets. The target selected was the Valentin submarine pens, that had been rendered unusable and abandoned since 617 Squadron's attack on 27 March 1945. Grand Slams were carried by Lancasters from No. 15 Squadron RAF and US Boeing B-29 Superfortress. Around 140 sorties were flown, testing a range of different bombs.
The photos below state "Grand Slam" payload. Nice job working out the bomb bay doors.


