Radiant

One Piece and Radiant have the same concept, where a young boy having a dream to become the strongest and finding something (Luffy wants to be Pirate King and find One Piece, Seth wants to be the strongest sorcerer and find Radiant). To achieve their dreams, they have to go through adventures to gain allies as well as information about where the things are placed. 

Both follow a similar pattern and premise. Both stories follow the protagonist moving from island to island to become stronger and finding their objective (the One Piece and Radiant) In both cases, the protagonists are seen as evil/the bad guys merely for who they are. > In One Piece, Luffy and his gang are seen are evil because they are pirates and pirates are 'evil' > In Radiant, Seth and other sorcerer's are seen as evil because they are sorcerer's Also, there is a semblance in the antagonists. > One Piece - the Marines > Radiant - the Inquisitors >>> The antagonists are law enforcers who try to catch the protagonists merely their 'occupation' and not by their character; it doesn't matter if they are good people and have not broken the law  read more 

If One Piece is in the sea, then Radiant is in the sky. Both anime is pretty similar, they travel to different islands, fight enemies, make friends and travel together. For One Piece, their journey is to find the treasure called "One Piece" while Radiant in the other hand is to find something called "Radiant" 

Radiant, much like Black Clover has an MC in a magic user's world but happens to be unique and different compared to the others. - MC starts off ridiculed - MC has a unique ability - MC has orphan background - MC is in a magic world Needless to say each of the MC's have very similar backgrounds and circumstances. Both good watches and worth checking out if you have seen the other. 

Black Clover and Radiant both follow the fairly standard battle shonen formula. The main character in both series wants to be the best sorcerer in the world/wizard king. The main difference between the two so far are that in Radiant Seth doesn't have a rival, while Asta has Yuno as a rival in Black Clover. Another difference is in Black Clover magic is used for everything while in Radiant sorcerers are hated except when they need to defeat a nemesis. In Radiant Seth actually uses magic, while in Black Clover Asta has no magic, but he uses anti-magic. 

Not magicians, but sorcerers • BOTH take place in a world of sorcery where magic and mythical creatures are commonplace • BOTH venture on a journey battling foes, demons, and other sorcerers  

Sorcerers vs. Wizards • BOTH take place in a world of sorcery where magic and mythical creatures are commonplace • BOTH venture on a journey battling foes, demons, and other sorcerers/wizards