Cleared SB a week ago this is what I've seen. Gonna skip over stuff already mentioned
Final Fantasy V
An Easter Island head is found under the sea in the 'ruby sea' area a direct reference to the Easter Island head found under the ocean in Final Fantasy V
Shinryu retains all his moves from Final Fantasy V including his famous "Tidal wave" abilitiy
Omega's first raid tier is a massive homage to Final Fantasy V inclusing bosses and enemies with things like Alte Right, Level checkers and even Exdeath himself to name a few, Exdeath even follows the same move set as he does in the original FFV boss encounter with him, casting Doom at the start and using high tier magic like Firaga, Blizzaga and Thundaga
Final Fantasy VI
Lord Hien shares the same musical theme with Cyan from Final Fantasy VI slightly remixed to fit Final Fantasy XIV
Hiens childhood name Shun is a reference to the Japanese name of Cyan Garamond's son Owain. Speaking of names Lord Kaien's name is Cyan's Japanese name
Gosetsu is seen fishing on a desserted island with a sleeping Yotsuyu alluding to how Celes had to catch fish for a poorly Cid.
Fordola is infused with the power to use Magicks much like Celes was
Number 24 boss found in the level 69 dungeon is a reference to a boss of the same name and design in Final Fantasy VI. It is also called Magimaster in the original release of Final Fantasy VI (III)
The magna rider boss and enemies share the design and name of enemies found in Final Fantasy VI
Doma is also the name of a nation in Final Fantasy VI that the empire is trying to take over, Final Fantasy XIV Stormblood draws a ton of story parrelels to Final Fantasy VI
The party find Hien on a cliffside similiar to how Cyan was found in the World of Ruin in Final Fantasy VI
The last boss of the level 69 dungeon is a reference to the Inferno boss sharing the same name and design
The Muud Suud enemies appear as late game monsters sharing the same colour pallete as the famous Humbaba monster
The Gorgias enemies appear in the game under the name "mammoths"
The Brainpain monsters appear as common enemies around Doma
Lakshimi appears as a Primal
Final Fantasy VII
The Samuarai's idle pose is the same as Sephiroth's victory pose
The Guard Scorpion boss from Final Fantasy VII appears as a boss in the final dungeon, it uses the same model seen in Mobius Final Fantasy which also comes from the Final Fantasy VII remake
An NPC shouts out to the Warrior of Light to "attack while it's tail is up!" a famous mistranslation from Barret that resulted in a nasty attack from the Guard Scorpion if the player chose to follow his advice
The Guard Scorpion is called "Magitek Scorpion" in the English localization where as the Japanese version retains its original name
A sidequest storyline in The Fringes involves a Miqo'te who believes that his father abandoned him as a coward. He later learns that, in reality, his father died protecting their village from monsters whose poison turned him to stone. This references the story of Red XIII and his father.
Aulus mal Asina is based on Hojo right down to the experimentation and design
Final Fantasy X
Ixion appears as a FATE boss looking similar to its Final Fantasy X appearence
Yojimbo appears along with Daigoro in a level 70 dungeon using the same model seen in Final Fantasy X
The idle pose while in the water is very similar to how Tidus lays in the water during many moments in the game
Final Fantasy XI
The Antlion enemies found in Final Fantasy XIV uses the same model as the Antlions in Final Fantasy XI with updated textures
The Matamata enemies found in Final Fantasy XIV uses the same model as the Matamata turtles in Final Fantasy XI with updated textures
The Chapuli enemies found in Final Fantasy XIV uses the same model as the Chapuli's in Final Fantasy XI with updated textures
The Crakclaw enemies found in Final Fantasy XIV uses the same model as the Craklaw crabs in Final Fantasy XI with updated textures
The Flying Shark enemies found in Final Fantasy XIV uses the same model as the Rockin in Final Fantasy XI with updated textures
The Ruszor enemies uses the same model as the Ruszor enemies found in Final Fantasy XI
The Kojin Beastmen are most likely based on the Quadav from Final Fantasy XI
The Cardian enemies are reused as enemies in Final Fantasy XIV
Final Fantasy XII
Zenos fuses together with Shinryu alluding to Vayne Solidor merging with Venat in the game's final battle
Final Fantasy XIII
The Chaochu use the exact same design as the Ochu from Final Fantasy XIII retaining the same moves and skills, these Ochu were first seen in Sohm Al (Hard)
Other FF stuff
There is a FATE in the Ruby Sea called "Agni's Philosophy" referencing the Final Fantasy tech demo for the Playstion 4 of the same name.