Simple ESP Open source

local Players = game:GetService("Players")

local function highlight(character)
    local h = Instance.new("Highlight")
    h.FillColor = Color3.fromRGB(255, 0, 0)
    h.FillTransparency = 0.5
    h.OutlineColor = Color3.fromRGB(255, 0, 0)
    h.DepthMode = Enum.HighlightDepthMode.AlwaysOnTop
    h.Parent = character
end

for _, v in pairs(Players:GetPlayers()) do
    if v ~= Players.LocalPlayer then
        if v.Character then
            highlight(v.Character)
        end

        v.CharacterAdded:Connect(highlight)
    end
end