The other condition, that I thought needed to go without saying, but I'll say it anyway- you can't say "God did it." Or say “They’re metaphorical” when each case clearly indicates a physical creature/object of supernatural being.
These passages are all from the KJV, other versions of the Bible have translated certain beasts into more reasonable animals- AGAINST their original wording, context and translation.
Satyr - Isaiah 13.21 "But wild beasts of the desert shall lie there; and their houses shall be full of doleful creatures; and owls shall dwell there, and satyrs shall dance there."
Original Word - śâ‛ı̂yr – Which can mean; shaggy; as noun, a he goat; by analogy a faun: - devil, goat, hairy, kid, rough, satyr
According to the commentaries of Wesley, Barnes, Clarke, Gill, Jameson, Fausset an Brown agree that this word is referring to the Demi-God/Devil of which is half man, half goat.
Firey Serpents - Numbers 21.6 "And the Lord sent fiery serpents among the people, and they bit the people; and much of Israel died."
Original Words - śârâph nâchâsh – śârâph coming from the word śâraph which means to burn, which is also applied to the highest class of angels- seraphim, the burning ones. However, śârâph could also mean poisonous. Which could either imply a creature of mystical origin, or a mistranslation. Your choice.
Cockatrice - Jeremiah 8.17 "For, behold, I will sent serpents, cockatrices, among you, which will not be charmed, and they shall bite you, saith the Lord."
Original Word - tsepha‛ tsiph‛ônı̂y – From an unused root meaning to extrude; a viper (as thrusting out the tongue, that is, hissing): - adder, cockatrice – It’s interesting to note that out of occurrences of this word being used in the bible, only once has it been used to refer to an Adder, the other 4 times, “Cockatrice”. The commentary of Jameson, Fausset and Brown refer to this creature as both a cockatrice and a basilisk.
Unicorns - Isaiah 34.7 "And the Unicorns shall come down with them, and the bullocks with the bulls, and their land shall be soaked with blood, and their dust made fat with fatness."
Original Word - rêm – This word has been used a total of 9 times in the entirety of the Bible, all times being translated as unicorn. However, all of the commentaries I have actually debate this translation, saying it might’ve been confused with local rams- or even rhinoceros.
Dragons - Mentioned 16 different times, just a one example. Nehemia 2.13 “And I went out by night by the gate of the valley, even before the dragon well, and to the dung port, and viewed the walls of Jerusalem, which were broken down, and the gates thereof were consumed with fire.”
Original Word - drakōn- Probably from an alternate form of derkomai (to look); a fabulous kind of serpent (perhaps as supposed to fascinate): - dragon. Interesting to note that this isn’t the only word used for “Dragon”- another one is “Tanniyn”, which refers to dragons-of-people (not people-dragons, but dragon-like in personality/royalty), so there is definitely a distinction between the two, that this is a physical dragon creature.
Leviathan - Job 41.1 "Canst thou draw out leviathan with an hook? or his tongue with a cord which thou lettest down?"
Original Word - livyâthân - a wreathed animal, that is, a serpent (especially the crocodile or some other large sea monster); figuratively the constellation of the dragon; also as a symbol of Babylon: - leviathan, mourning.
All of the commentaries I have debate on what the Leviathan actually is, some try and reason that it is a crocodile from the Nile, or perhaps a whale- but no-one is really sure. An interesting commentary on this creature is from Barnes.
The rest don’t need etymology lessons;
Talking Snakes - Genesis 3.1 "Now the serpent was more subtil than any beast of the field which the LORD God had made. And he said unto the woman, Yea, hath God said, Ye shall not eat of every tree of the garden?"
Talking Donkeys - Numbers 22.28 "And the LORD opened the mouth of the ass, and she said unto Balaam, What have I done unto thee, that thou hast smitten me these three times?"
Talking Trees - Judges 9:9 "But the olive tree said unto them, Should I leave my fatness, wherewith by me they honour God and man, and go to be promoted over the trees?"
Half-Human, Half Angels (Nephilim, or Giants) Genesis 6.4 - "There were giants in the earth in those days; and also after that, when the sons of God came in unto the daughters of men, and they bare children to them, the same became mighty men which were of old, men of renown."
Animated Objects (In this case, an animated, flaming sword) - Genesis 3.24 - "So he drove out the man; and he placed at the east of the garden of Eden Cherubims, and a flaming sword which turned every way, to keep the way of the tree of life."
And who says I don’t know The Bible?