Well of course unseen entities fall into the category of little g gods. And yes, they are real and do exist, contrary to the claims that many are (surprisingly) trying to make here.
Here is a demonstration of the "power" of one of these gods:
Matt. 4:
8 Again, the devil taketh him up into an exceeding high mountain, and sheweth him all the kingdoms of the world, and the glory of them;
9 And saith unto him, All these things will I give thee, if thou wilt fall down and worship me.
Any being who could do the above, notwithstanding the "truth" of any of it, could certainly be considered a real entity and thus, a little g, god, which IS how Paul describes this adverse (to God and man) spiritual entity in citings such as Acts 26:18, 2 Cor. 4:4 and Eph. 2:2.
We also know from scriptures that there are anti-Christ spirits. IF Christ is a Spirit or The Spirit OF GOD, which IS the case, and there are such spirits in the ANTI-Christ sense, then we might even consider the "god status" of such beings, and even observe they are ANTI-God gods.