Miled, 143 bytes

I don't know if a language in alpha is allowed, but here it is.

def f cS "x" <: if:: & div 3 x div 5 x "FizzBuzz" else if:: div 3 x "Fizz" else if:: div 5 x "Buzz" else ->str x :> join "\n" map f ;! ..= 1 100

TIO (read: Try It Offline)

_{A little note on this language: it's created by me. The current release is the first release of the language and it's still in alpha, so expect bugs. I haven't encountered any yet, so I think, maybe the best way to test it is to make more people use it! So if you find bugs, please report it. And I'm just a hobbyist with few coding experiences, so please give me advices. Thanks!}

Miled, ¹⁴³127 bytes

I don't know if a language in alpha is allowed, but here it is.

-16 by myself. Yes. I was dumb.

join "\n" map fn cS "x" <: if:: div 15 x "FizzBuzz" else if:: div 3 x "Fizz" else if:: div 5 x "Buzz" else ->str x :> ..= 1 100

TIO (read: Try It Offline)

_{A little note on this language: it's created by me. The current release is the first release of the language and it's still in alpha, so expect bugs. I haven't encountered any yet, so I think, maybe the best way to test it is to make more people use it! So if you find bugs, please report it. And I'm just a hobbyist with few coding experiences, so please give me advices. Thanks!}