prepend a column to grid

How would you prepend a column to a grid? I have seen Appending and Prepending columns to a dataset in 10.0.2.0
but that is applied to datasets and I want to retain things as a grid.
I need to prepend an "offset" column to a data set and so far haven’t seen any easy way of doing this that retains the grid structure (I’ve seen a "columns" method but it does not seem to retain the same alignment with the rest of the columns). Could use some help.

Update
I’m still having some issues with the solns proposed so let me post the code I am using–maybe I am just asking the wrong question

I’d like to be able to prepend a column that shows the offsets in hex

hexdata = ReadByteArray["..<some file>"];
nbytes = Length@hexdata;
addrs = Table[BaseForm[#, 16] &@x, {x, 0, nbytes/16 // Floor}];

hexshowAmount = nbytes/8;
hex = (hexdata[[1 ;; hexshowAmount]] // Normal);

tbl = hex // Partition[#, UpTo@16] &;
nrows = Length@tbl;
ncols = Length@tbl[[1]];

myFunc[val_] := PrimeQ[val]; (* Must Return True or False *)

labels = Flatten@
    Table[If[
      myFunc[tbl[[i]][[j]]], {i, j} -> Hue[RandomReal[], .2, .9], 
      Nothing], {i, nrows}, {j, ncols}] // Quiet;

(* original method *)
outputhex = 
  tbl // Grid[Map[BaseForm[#, 16] &, #, {2}], Frame -> All, 
     Alignment -> Center, Spacings -> Center, 
     Background -> {None, None, labels}, ItemSize -> {2, 2}] &;

(* current method *)
Multicolumn[BaseForm[#, 16] & /@ hex, 16, 
 Appearance -> "Horizontal", Frame -> All, Alignment -> Center, 
 Spacings -> Center, Background -> {None, None, labels}, 
 ItemSize -> {2, 2}]

Which results in

I guess another issue is that I have since found using Multicolumn to suit my purpose better. Is there a way to prepend Multicolumn that is easier?

UPDATE2

Ahh feel like a dummy

Join[{Range[5]}, Transpose@#] &@%[[1]] // Transpose // Grid

However this will mess up the highlighting so need to change the line

labels = Flatten@
    Table[If[
      myFunc[tbl[[i]][[j]]], {i, j } -> Hue[RandomReal[], .2, .9], 
      Nothing], {i, nrows}, {j, ncols}] // Quiet;

into

labels = Flatten@
    Table[If[
      myFunc[tbl[[i]][[j]]], {i, j+1 } -> Hue[RandomReal[], .2, .9], 
      Nothing], {i, nrows}, {j, ncols}] // Quiet;

Hoping there is a less hacky way to accomplish this tho.

array = Array[a, {4, 5}];

grid = Grid @ array

newcolumn = Array[b, 4];

newarray = Transpose[Prepend[newcolumn]@Transpose[array]];

Grid @ newarray

newarray2 = MapThread[Prepend, {array, newcolumn}];

newarray3 = Join[List /@ newcolumn, array, 2];

newarray == newarray2 == newarray3

newgrid = Grid @ Transpose[Prepend[newcolumn] @ Transpose[First @ grid]]