How to find the last player still in the game?

This is what I got, I'm trying to make a battling game, so basically, I'm putting a tag into players who is battling when they are teleported in to the battle zone. So when someone died, the tag will be remove when they are spawned in the lobby so if who ever have the tag, it means that they are still in the game. the problem is that I'm trying to make a last survivor but I'm not sure how to count the number of players with tag.

local stat = game.ReplicatedStorage:WaitForChild("Stats")

for i, plar in pairs(game.Players:GetChildren())do
	if plar.Character then
		plar.Character.HumanoidRootPart.CFrame = spawns[1].CFrame
		table.remove(spawns,1)
		local gametag = Instance.new("BoolValue")
		gametag.Name = "GameTag"
		gametag.Parent = plar.Character -- Add tag to the players
	end
end

local gamecountdown = 20
repeat wait(1)
	stat.Value = "Time Left: "..gamecountdown
	local player = game.Players:GetChildren()
	for i = 1, #player do
		local v = player[i] -- making a table of players
		print(player)
		if v.Character:FindFirstChild("GameTag") then -- getting only the players with tag in the table
			-- See if there is only 1 player with a tag
			if #v == 1 then -- error: attempt to get length of an Instance Value
				local DataStore2 = require(1936396537) -- Datastore2 stuff
				local datagold = DataStore2("Golds", v)
				stat.Value = "Winner: "..v.Name
				datagold:Increment(5)
			break
				elseif #v == 0 then -- if the 2 last player kill each other at the same time
				stat.Value = "Everyone died..."
			break
			end
		end
	end
	gamecountdown = gamecountdown - 1
until gamecountdown == 0

-- The aftermath of the match, removing the tag from everyone to make sure that there's none
stat.Value = "Game Ended..."
for _, plr in pairs(game.Players:GetChildren())do
	if plr.Character then
		plr.Character.HumanoidRootPart.CFrame = game.Workspace.SpawnLocation.CFrame
		if plr.Character:FindFirstChild("GameTag")then
			plr.Character:FindFirstChild("GameTag"):Destroy()
		end
	end
end

Ask me any question if there is a variable there that I forgot to include as this is only part of the script. Help please. Thank you!

There are few things that you have to add and edit in your code, which will be helpful in finding the player with tags.

-- First, in the starting, create an empty table 
-- Line 7
local TableWithTags = {}

-- Now, we will add the name of the player in the local table created
-- Line 10 
table.insert{TableWithTags, plar.Name}

-- Now, instead of looping with the player having tag, we will loop in the table created above
-- Adjust the lines of the looping of the tables accordingly
for a, b in ipairs(TableWithTags) do
	if a[2] == nil then -- Checks if no more than one player is left 
		-- YOUR CODE
	end

	if a[1] == nil then -- Checks if no one is left
		-- YOUR CODE
	end
end

-- If you want to remove the tag from the player when he/she dies
-- You have loop through the table
for i, v in ipairs(TableWithTags) do
	if TableWithTags[i] == plr.Name then -- Checks if the name of the player killed is in the table
		table.remove(TableWithTags, i) -- Removes the player from the table
	end
end

Lemme know if it helps!