Question

有没有I think it good这种说法吗

Answer 1

错误。应该用从句，be动词不能省略。
I think it is good.

Answer 2

这句话严格讲是不地道的，原因在于动词think的用法。think作为动词，一种常哗前见用法是think+形式主语it+形容词（+动词不定式）。因此这句话应该改为I think it good （to do ...）. 更多类似用法： I think it better not to try. 我认为还是不要尝试宽谈的为好。 I don't think it right to smoke in public. 我不认为在乱巧清大庭广众之下是恰当的。 They think it worth reading times and times again. 他们认为它（这本书）值得反复阅读。