Honorable Mentions:
Bunny & Canard, Siege Walker, Satoru - These ubers have no shield pierce or are lacking in shield pierce.
Lucifer, Amakusa - These ubers in particular have surge attacks or multi hit which gives them better combat against shields. Their offensive output is extremely high and allow them to be arguably #5 or higher depending on how heavily you weigh shield piercer.
Stats taken from MyGamatoto & Spica.
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