You really havejust ONE phone that is called HTC One, the other phones got designations added to HTC One. Now I am talking about phones released in Europe, Asia got other variants.
It started in 2012 with HTC One V, S and One X (One X the stronger of them, and One V the smallest). To be followed in late 2012 by HTC One X+, which is a stronger One X with a larger battery. There was a 4G version of One S called One SV as well
Then february 19th 2013 HTC One got announced, to be followed later that year by HTC One Mini (with a smaller display) and a HTC One Max which is a HTC One with a larger display (5.9″ compared to 4.7″).
So, to do this in list form
2012
- One V
- One S
- One SV
- One X
- One X+
2013
- One
- One Mini
- One Max