TableForm[
    Table[Plot[Sin[ n x], {x, 0, 2 Pi}, ImageSize -> {150, 150}], {n, 1,
15}]
]

table = Table[Plot[Sin[n x], {x, 0, 2 Pi}, ImageSize -> {150, 150}], {n, 1, 15}];

TableForm[ArrayReshape[table, {3, 5}]]

Multicolumn[table, {3, 5}]

Grid[Partition[table, 5]]