Both have a main character that don't know anything about playing their respective show's game and are later taught them, but are also similar because they both practice martial arts, both show's have colorful cast of characters, and both show's depict characters fighting in a tournament to hone their skills in a game, Buddyfight is a card game battle and Gundam Build Fighters Try is a gunpla battle. Both main characters relate their martial art use in their battles.
Taking place several years later. Both anime has new characters in the same universe who enter the world of GunPla( Gundam Build Fighters) and CardFight Vanguard. The original characters from previous season will make an appearance to help the new main characters out. One series is a mecha and the other a card game. Both anime airing this Fall 2014.