The first law concerning defining and what to do about clean and unclean things is the law defining clean and unclean meats:
That is, God first defined to Aaron and Moses which animals were considered 'clean' and thus would not make Israel unclean, so they were safe to kill and eat their meat but also defined, 'unclean' animals that would make Israel unclean, thus make them unclean:
Leviticus 11:46-47
“These are the regulations concerning animals, birds, every living thing that moves about in the water and every creature that moves along the ground....between the unclean and the clean [animals], between living creatures that may be eaten and those that may not be eaten.”
So, God list all animal categories based on how they move/where they usually are to define what is a clean animal and what is an unclean animal:
He first starts with land animals (that is animals who walk on land: including Land Mammals and reptiles)
Defining clean and unclean land animals
A clean land animal that can be eaten is defined as an animal that has divided hooves and also 'chews cud' (That is chewing food [often grass/hay]: this specifically means this food has already been partially/fully digested but is being chewed on for a second time to help digestion):
Leviticus 11:2-3
"...Of all the animals that live on land, these are the ones you may eat: You may eat any animal that has a divided hoof and that chews the cud."
And God stresses in order for a land animal to be a clean animal (and thus okay to eat) it had to have both of these characteristics:
Leviticus 11:4
“There are some that only chew the cud or only have a divided hoof, but you must not eat them."
It wasn't enough to just have divided hooves yet not 'chew cud' (like a pig does):
Leviticus 11:7
"...the pig, though it has a divided hoof, does not chew the cud; it is unclean for you."
Nor was it enough to just 'chew cud' yet didn't have split hooves (Like a Rabbit does):
Leviticus 11:6
"The rabbit, though it chews the cud, does not have a divided hoof; it is unclean for you."
No, a truly clean land animal had to have both split hooves and chew cud!
These two characteristics shorten down/point to the list of clean land animals to only mammals in the Bovidae (this would be animals such as cows, sheep, goats, gazelles, buffalo, and bison) and Cervidae (Deers) family (Both these animals are also commonly called 'Ruminates' because they possess a special stomach called a ruminate that allows them to 'chew the cud').
So, this meant Israelites could only eat the meats of Bovine and Deer Ruminates, which would include:
Sheep,goats,gazzels,buffalo,bison,cows,deers,moose,and elk
This also means the rest of the land animals (all other families of land mammals like the feladae or canine family and all reptiles) are all unclean animals:
This means the Israelites were not to eat the meat of any other land animals, this includes:
Rabbits,camels,pigs,seals,frogs,hippos,cats,dogs,horses,donkeys,zebras,lizards,snakes,bears,foxes,kangaroos,rats,monkeys,apes,turtles etc.
They were to never eat the meat of any of these unclean land animals, or they would become unclean and defile themselves and God's temple.
Defining unclean sea creatures
Next God moved onto what sea creatures were clean and unclean animals that lived primarily in (or strongly associated) with water (this includes fish, aquatic mammals (Cetacea), crustaceans, cephalopods, mollusks, and isopods)
A clean sea creature is defined as one having scales and fins:
Leviticus 11:9
“Of all the creatures living in the water of the seas and the streams you may eat any that have fins and scales."
Out of all the sea creatures in Earth's waters, only fish can meet these two qualifications of having both scales and fins; and not even all fish meet these qualifications: a catfish is a fish that has fins but no scales:
So, this means Israelites could only eat the meats of scales and finned fish, this includes:
Tuna, Salmon, Tilapia, carp, bass, perch, flounder, trout etc.
this means all aquatic mammals (Cetacea), crustaceans, cephalopods, mollusks, and isopods are unclean, this includes:
crabs, shrimp, lobster, shark, stingray, eels, catfish, oysters, squids, jellyfish, octopus, dolphins, whales etc.
An Israelite was to never eat any of these sea creatures, or they would become unclean and defile God's temple:
Leviticus 11:12
"Anything living in the water that does not have fins and scales is to be regarded as unclean...you must not eat their meat..."
Defining clean and unclean flying creatures
Next God moved onto what flying creatures (that is Birds and Bats) were considered clean and unclean animals that are capable of flight into the air:
But unlike the other two sections of animals mentioned before; God does not mention two specific characteristics to define a clean flying creature from an unclean one: instead, he just mentions a list of all unclean flying creatures:
Leviticus 11:11-18
"You may eat any...bird. But these you may not eat (are unclean): the eagle, the vulture,...the red kite, the black kite, any kind of falcon, any kind of raven, the horned owl, the screech owl, the gull, any kind of hawk, the little owl, the great owl, the white owl, the desert owl, the osprey, the cormorant, the stork, any kind of heron, the hoopoe and the bat."
Since God gives the list of unclean flying creatures, we know without defining characteristic all the unclean flying creatures:
Eagles,Vultures,Hawks,Red & black Kites,Horned,Screech,Little,Great,white and Dezert Owls,Falcons,Ravens,Seagulls,Ospreys,Cormorants,Storks,Herons,Hoopoe and Bats
So, it seems all Bats, pretty much all Birds of Prey/Raptors are directly mentioned (this includes very carnivorous birds like Eagles, Owls, and Vultures etc.) along with Ravens, Some seabirds(seagulls), Hoopoe, and some aquatic birds (specifically the clades 'Suliformes' and flying birds in 'Aequornithes') are all unclean flying creatures.
An Israelite could never eat the meat from these creatures, if they did, they would become unclean and defile God's holy temple/Prescence.
This leaves all the other flying creatures (all birds) as clean by absence from God's list of unclean ones, this would mean:
Chickens,Ducks,Geese,Goose,Swans,Quail,Potridge,Songbirds,Doves,Pigeons,Hummingbirds,flamingoes,Parrots Ect.
Are all clean flying creatures, and thus are okay for an Israelite to eat
Next God moves onto the final category of animals:
Defining clean and unclean Insects/other small creatures
God openly defines all insects as unclean except for flying insects that have joined back legs for jumping:
Leviticus 11:20-42
“All flying insects that walk on all fours are to be regarded as unclean by you....Every creature that moves along the ground is to be regarded as unclean; it is not to be eaten. You are not to eat any creature that moves along the ground, whether it moves on its belly or walks on all fours or on many feet; it is unclean....There are, however, some flying insects that walk on all fours that you may eat(are clean): those that have jointed legs for hopping on the ground."
So, the only insects that are clean are flying insects with jointed legs for hopping on; these two characteristics would include only most of the order of Orthoptera (which includes insects like crickets, locusts, grasshoppers etc.)
God confirms these are the insects he was referring to with these characteristics when he mentioned the actual clean insects in a list:
Leviticus 11::22
"Of these you may eat any kind of locust, katydid, cricket or grasshopper."
This means all other insects, arachnids, and mollusks that lived on land and fly are all unclean; this would include:
Beatles,spiders,scorpions,butterflies,moths,flies,bees,walsps,worms,catipillars,grubs,ants,slugs,snails etc.
An Israelite could not eat the meat (or the entire insect or mollusk) of these animals, and if they did, they were considered unclean and defiled God's temple/Prescence.
With all the animals on Earth covered, God concludes the laws of clean and unclean meats with warning Moses and especially Aaron to teach Israel to define what animals were clean and unclean before they choose to kill them and eat their meat, so they did not defile themselves by eating unclean animal's meat and thus defile his holy temple and his Prescence.
Leviticus 11:43-47
“Do not defile yourselves by any of these creatures. Do not make yourselves unclean by means of them....You must distinguish between the unclean and the clean, between living creatures that may be eaten and those that may not be eaten.”