Beyazsakal:
Based just on his brute strength alone, Newgate blocked a two-handed downward swing from the giant Vice Admiral John Giant with only one hand on his bisento, and extinguished the flames of one of Akainu's molten rocks with just a single breath. Whitebeard also prevented a massive paddle ship (captained by Squard) from further advancing using only one hand.
Jozu:
Jozu has outstanding brute strength, comparable to that of the Giant Squad Marines, if not greater. He picked up and hurled an immense iceberg at a great distance at the giants protecting Marineford. The iceberg was so enormous that it was at least ten times as big as any of the Giant Squad's members. Thus, Jozu has demonstrated one of the greatest strength feats seen in the series, though it is currently unknown how losing his right arm will affect his strength.
Jaguar D. Saul:
Being a giant, he possessed almost unbeatable strength, which was, in fact, greater than that of most giants. He could easily lift a Buster Call ship up out of the water to slam it back down and destroy it (a Buster Call ship's size was several times the size of a giant at the time).
Monkey D. Garp
Garp is one of the most powerful fighters seen in the series so far. Although rather old, Garp still possesses an incredibly high amount of physical strength. He is able to throw iron cannonballs as if they were baseballs (at faster than cannon speeds), break through brick walls and cannon stands with his fists, and both carry and throw a gigantic ball and chain many times bigger than the Thousand Sunny.