Is there a better way to script MouseButton1Click?

#What you could do Well remastered box isn't wrong, you can use Tables and loops.

#Tables/Arrays These are variables that have multiple values inside of them, and they're written in this form: Table = {5/2,true,BrickColor.new(1)}. You address the value inside the table like so: Table[1] if we were still using the first table it would give you 2.5. Now by default you address each value by using numbers, but you can set each iterator. For example: Table = {a = "Hello", 4 = "LOL"}. This is called a Dictionary where each iterator is defined by a string in this example.

Another thing you can do with Tables is have tables inside of tables... Table = {1,{3,2},3,"Table-seption"}

#For Loop We're talking about a for loop that actually uses an iterator also, which is the "i" most people use, even though it can be anything most people, myself included, also use i to mean iterator...

for i = 1,10 do --i for Iterator; code will repeat 10 times.
--CODE
end

You put the code in the middle and it will run the chunk of code within it for however many times. Here's a diagram to maybe help you understand it better. What we can do is use the function pairs. In the example, i the iterator is labeled 1-4, but later in the table it says c = 12, c becomes the new iterator so that's why it prints

c 12

Table = {1,2,3,true,workspace.Part,412+32/2} --Another example, yes you can put full math equations in here...
for i,v in pairs(Table) do
     print(i,v) --Print the iterator and the value
end

#Final Code I used 2 for loops and a single dictionary.

local Buttons = {"Blue" = {"rbxgameasset://Images/blueS", "Really blue"},"Black" = {"rbxgameasset://Images/blackS","Black"},"Green" = {"rbxgameasset://Images/greenS","Lime green"},"Red" = {"rbxgameasset://Images/redS", "Really red"}, "White" = {"rbxgameasset://Images/whiteS","Lily white"}, "Yellow" = {"rbxgameasset://Images/yellowS", "Bright yellow"}}

for _,v in pairs(BLKGui:GetChildren()) do --We don't really need i so replace it with _, it's a habit; GetChildren returns a function
     if v:IsA("GuiButton") then --If the v is a GuiButton of any type(ImageButton or TextButton)
          v.MouseButton1Click:connect(function()
		newblock.BrickColor = BrickColor.new(Buttons[v.Name][2])
 	        colorselect()
    	        color = Buttons[v.Name][2]
   		wait()
   		v.Image = Buttons[v.Name][1]
	end)
     end
end

Hope it helps!