Padding list within lists

With[{n = Max[Length /@ list]}, PadRight[#, n, Last @ #] & /@ list]

PadRight[list, Automatic, list[[All, {-1}]]]

{{1, 1, 1}, {1, 1, 1}, {1, 1, 1}, {1, 6, 6}, {1, 4, 4}, {1, 3, 5}, {1, 3, 2}}

The 3rd argument can also be Take[list, All, -1].

Clear[pad]
pad = Function[list,
   PadRight[#, Max[Length /@ list], Last@#] & /@ list
   ];
pad@{{1}, {1}, {1}, {1, 6}, {1, 4}, {1, 3, 5}, {1, 3, 2}}

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