Final Fantasy: Unlimited

Two young characters venture into an unknown world inhabited by large beasts who are often controlled by strange enemies. They befriend attractive do-gooders and one-by-one fight through the immediate underlings of the world's evil ruler. Sound familiar? 

Both are based on popular JRPG series from Square Enix as well as focusing on young main characters being placed in dangerous situations in a unusual world. 

When it comes to the final fantasy games, the base concept is the 4 warriors of light fighting chaos, in which FFU is hugely inspired and based off of. Shield hero has this same base concept of 4 heroes within the same world to fight against an entity of chaos. FFU is a classic in this genre which has been getting popular in recent times. Both anime has the characters meeting new monsters and fighting monsters, as well as meeting characters with their own set of powers. Both anime features a giant bird-like creature in which people can ride or use ĺike a horse. Both use a tree-like upgrade system either through a shield or by upgrading a gun with different bullets to get stronger. read more 

Nobuo Uematsu works on soundtrack, and both are in the genre of fantasy.