I consider the late 80's to mid 90's to be the best years for animated films. During those years, Disney wasn't completely dominating the world of animation, and we got classic fantasy films from Don Bluth and others. Many of those films were somewhat lighthearted but had strong dark overtones.
My list includes:
An American Tail
The Brave Little Toaster
The Land Before Time
All Dogs Go to Heaven
Rock-A-Doodle
FernGully
We're Back! A Dinosaur's Story
The Pebble and the Penguin
Pippi Longstocking
Anastasia
My list includes:
An American Tail
The Brave Little Toaster
The Land Before Time
All Dogs Go to Heaven
Rock-A-Doodle
FernGully
We're Back! A Dinosaur's Story
The Pebble and the Penguin
Pippi Longstocking
Anastasia