Certainly! There are several anime series with one season and 20 or more episodes that offer rich storytelling and character development. One example is "Steins;Gate," a thrilling science fiction anime that consists of 24 episodes. It follows the eccentric Rintarou Okabe, a self-proclaimed mad scientist, and his friends as they accidentally discover time travel. The series delves into the consequences and ethical dilemmas of manipulating time, keeping viewers engaged with its intricate plot twists and emotional depth. Another notable mention is "Cowboy Bebop," an iconic space western anime comprising 26 episodes. It follows a group of bounty hunters traversing a futuristic solar system, blending elements of action, comedy, and noir. With its memorable characters and captivating jazz-infused soundtrack, "Cowboy Bebop" has become a beloved classic. Both series offer substantial content within a single season, delivering immersive experiences that will keep you engaged throughout their runtime.