The first commandment:

>Thou shalt have no other gods before me. — Exodus 20:3

hardly states that there *are* no other gods, only that the Israelites must ignore any gods other than their own one true God.

But "other gods" need not be literal spiritual beings.
Anything that people give their loyalty to, ahead of God, would be considered another "lord" or "master".

One obvious example of a real "other" god is Satan.

If you accept answers based on the New Testament, it quite explicitly names Satan as *the* god of this world:

>But if our gospel be hid, it is hid to them that are lost:
>In whom **the god of this world** hath blinded the minds of them which believe not,…
>— 2 Corinthians 4:3,4

Similarly, it gives examples of how one can serve only one master:

>No servant can serve two masters: for either he will hate the one, and love the other; or else he will hold to the one, and despise the other. Ye cannot serve God and mammon.
— Luke 16:13

and in this case "mammon" is simply wealth or money, not a literal god, but a master or lord nevertheless.