I would say JW or LDS but by Scripture definition of baptism they are not Christian or even close. By the dictionary definition they are Christian since they use Bibles and believe in Jesus. I will assume here that baptism with water and the Trinitarian formula is correct since it is in Scripture and the dictionary is not.
So who does that leave? Well we would have to look at the sects that have one foot on both side of the line. Who is barely Christian? Who is in the gray zone? Why the SDA’s of course. They are Christian -barely - but Christian never the less. Things like the antiChrist (pope), soul sleep, Sola Fida, Sola Scriptura, their bizzare founder (is that Twilight Zone music I hear playing in the background?), vegan and vegatarianism, the whore of babylon (the Catholics), etc…
So much to talk about and they ARE Christian!