If you liked
Ueki no Housoku
|
...then you might like
Fairy Tail
|
Both anime prominently feature a character whose beliefs about friendship, loyalty, and doing what's right motivates them. Natsu can be hot-headed and may enjoy fighting more than Ueki, but both are willing to sacrifice pretty much everything for the sake of doing what's right and/or protecting their allies and friends. If you're looking for a show that inspires you to root for the good guys because you get swept up in the emotion of fighting for what you believe in and sticking by your friends no matter what, both Law of Ueki and Fairy Tail are exactly what you're looking for.
If you liked
Toshokan Sensou
|
...then you might like
Chocolate Underground
|
One bans chocolate, the other bans books. Where Chocolate Underground is more of a child-friendly view on a dystopian future, Toshokan is a more "grown-up" take on the same ideas of government tyranny, personal liberty, and those who would resist. Toshokan has more violence and a romance storyline and is geared more towards adults.