The first two that come to mind is a young man named John Vance, whom the Batman of Earth-One early in his career recruited to be his crimefighting partner. This association was shortlived as the teen athlete didn't have his heart into this new way of life. Years later, he would assist his former partner and Robin in a case of Birrell Banter, whom the original Dynamic Duo took down and had returned once more.
Then there was Hugo Marmon, a dynamic acrobat who years ago on Earth-Two was known as the Bat-Man, wearing an outfit very similar to that of the hero by the same name. When he attempted to revive his slagging career, he was tricked by a criminal into completing as protector of Gotham City, which masked the hoodlum's own hoods' felonies. Eventually after the truth was revealed, Bat-Man resumed his circus career and his "successor" regained the title he was afforded to by a law in the city as the sole Batman.