Not by size, but by how dangerous they probably were.
Notify me if you think I should add any species, or something like that.
http://www.ranker.com/list/giant-killer-theropods/the-enraged-balaur,
Carcharodontosaurus Saharicus
The only rival to Spinosaurus, it had over 13 meters from snout to tail, its teeth were like of a shark, and it probably preyed on Ouranosaurus. It lived in Cretaceous North Africa. This dinosaur was discovered in 1927, but a new species, C. Iguidensis, was described in 2007 by Paul Sereno.
Spinosaurus Aegyptiacus
This huge animal was the biggest Theropod ever, and would eat anything that had flesh. It lived in Cretaceous North Africa and rivalized with other predators like Carcharodontosaurus. It didn't rely on it's bite, but actually on its fierce claws. It could reach over 17 meters length and about 7 meters high. It had a crest on top of its head, and a 2 meter tall sail on its back, the sail was probavly used for temperature control. It was a great swimmer and it loved to eat fish, but would not refuse some good dinosaur meat.
Another species of Spinosaurus is S. Maroccanus.
Suchomimus Tenerensis and Oxalaia Quilombensis
These spinosaurs lived in North Africa and Brazil, respectively, and had sizes of 11 and 14 meters. Suchomimus was probably the most lethal dinosaur ever, for fishes. Oxalaia was probably very close to Spinosaurus in all aspects.
Giganotosaurus Carolinii
This was definitly the biggest of all avetheropods, it had about 15 meters in length. It was undoubtly a sauropod killer, it hunted huge Argentinosaurus, and it probably was very oportunistic, as it probably hunted in packs. It lived in cretaceous Argentina, a place where the biggest dinosaurs were. Groups of abelisaurids, Mapusaurus and Tyrannotitan are probably the only competition this monster faced, and still, it was bigger then all other Theropods in this area, amd the second in the whole world.
Bahariasaurus Ingens
The Bahariasaurus is very unknown, very little remain have been found, and it has already been classified as a Tyrannosaur, a Carcharodontosaur, and most recently, a Ceratosaur, because its remains are very close to that of the better known Deltadromeus Agilis, of which Bahariasaurus may be a synonym. The size estimates vary from 8 meters to 14 meter. It lived in cretaceous North Africa.
Mapusaurus Roseae and Tyrannotitan Chubutensis
These killers are placed together because they are both considerably recent discoveries of giant carcharodontosaurs in cretaceous Argentina. They have estimates of 10 to 13 meters and probably they hunted in packs, just like Giganotosaurus, to take down huge sauropods.
Saurophaganax Maximus
It may be a synonym of Allosaurus, but generally it is considered as a separate genus. It lived in jurassic North America, its estimates are of about 12 meters, but this is not confirmed.
Aerosteon Riocoloradensis
This neovenatorid from Argentina has inovated the breathing of dinosaurs, having air-sacs much like a bird. This probably made it run faster and for more time, while chasing prey. The remains found made possible the 9 meter estimate, but it was probably bigger, as this individual was apparently not fully mature.
Torvosaurus Tanneri
This colossus was the biggest theropod of the jurassic period, it lived in North America and Portugal, on North America, they reached up to 9 meters, but on Portugal there are estimates of 12 meters. This was truly the Terror of the Jurassic, it was probably the biggest Megalosaur ever.
Acrocanthosaurus Atokensis
This was the second biggest theropod of cretaceous North America, being over 11 meters in lenght. Once this dinosaur was called Acracanthus, and another species, Acrocanthosaurus Altispinax, has also been described, but now, it is believed its remains were from Becklespinax. Its prey probably included the giant sauropod Astrodon.