Angels are certainly mentioned in the Bible, but demons are not referred to as "demons" (Revelation 12:7).

I'm sure that I will add more information on this subject as I learn more, but to give you some basic information, I have found the following:

There were probably two Archangels at the beginning of time. One was Lucifer and the other is Michael. Lucifer is the fallen archangel that is also known by many names - including Satan.

Michael the Archangel is mentioned by name in Jude 9. Lucifer is mentioned as fallen in Isaiah 14:12-14 and Ezekiel 28:12-17.

While there are probably millions and millions of angels (Psalm 68:17), I only found one that was named, thus the most well known; Gabriel (Luke 1:26).

The Seraphim are in Isaiah 6:1-6 and are referred to as being "above the throne", whereas the Cherubim are referred to as being "beside the throne" (see Ezekiel 10).

I noted that Cherubim is plural, thus one of these beings is a cherub (Ezekiel 41:18).  Based on that, probably a single Seraphim is a seraph.

Cherubim are also mentioned in Genesis 3:24; Exodus 25:18-20; Psalm 80:1; Psalm 99:1 and Hebrews 9:5.

Since typing these references for you, I have realized that it may be a little confusing. The long description in Ezekiel 10 is describing a real living being, whereas some of the other references refer to the mercy seat of the ark of the covenant; which represent the cherubim, but are just parts of a structure; not the living beings.