Anyone know how to make a tested Particle saving script?

No one is going to write a script for you. The more you spam, you might just get moderated. Learn the basics before trying to make a game.

Before reading on, this is assuming you know how to do DataStore

If you are trying to make a particle saving script what you would need a StringValue. Start with a ServerScript:

game.Players.PlayerAdded:Connect(function(plr)
    local Particles = Instance.new('StringVaue')
    Particles.Parent = plr
    Particles.Value = 'Nothing'
end)

Set the Value of particles to the name of the particle, then, simply save the data on leave or button.

Then, make another ServerScript, call it 'Particle Loader'

than load the particles

game.Players.PlayerAdded:Connect(function(plr)
    if plr:WaitForChild(Particles').Value == 'Fire' then
        -- add fire particle
    elseif plr:WaitForChild('Particles').Value == 'Water' the n
        -- add water particle
    end
end)

This is a simple idea on how to do it. Remember, learn before doing. You won't make a good game if you can't do things you self. Search, google, and read the Roblox Wiki before asking.

If this helped you in anyway, please Upvote and accept answer :D

-- Your Orange, BlackOrange3343