9 titles recommended if you like Leviathan
The Most Notorious "Talker" Runs the World's Greatest Clan
The Heroic Legend of Arslan
The Orbital Children
Birdy the Mighty: Decode
KILL BLUE
The Weakest Tamer Began a Journey to Pick Up Trash
Space Pirate Captain Harlock
The Tatami Time Machine Blues
Fate/Grand Order Absolute Demonic Front: Babylonia