Before matching them up, it should be prefaced that this list will only count canon forms shown in the manga and anime, so Ichigo's Hell form, for example, which is only shown in a movie ...

The Vizored are powerful Soul Reapers with Hollow powers, but who's the strongest ... Lorde-like form and decimated Ulquiorra and almost killed Uryuu Ishida. After this, Ichigo feared his Hollow ...