Let me name a few, and everyone else can add more:
The early beta bundle submachine guns,
the Lag (an advanced 37mm variant—I hadn’t even heard of it!),
the Italian 
Panzer III N (which ended up as a copy-paste and would be better suited at BR2)
the Panzer IV Command variant (now able to withstand 76mm shells from the front),
the Soviet Valentine (intentionally nerfed in WT—all equipped with 6-pounder guns),
the German rocket vehicle (lacks proper artillery and should be moved to BR3),
the M8 Greyhound (should be in the TT like the Puma, given its high production numbers).
Feel free to add more examples.
I think I bought that during one of their sales as I would have never considered paying full price for it… 
