Beast Type. (no relation to Ultra Beasts)
Beast-type Pokemon are big, rugged, and wild! These Pokemon resemble normal animals for the most part, but showcase the ferocity of nature and are extremely dangerous in most situations---only high-level Pokemon Trainers should attempt to tame them!
Beast Pokemon typically excel in Attack and utilize various moves that often have a drawback, such as recoil or a chance of self-confusion. They're usually not ones for trickery, leaving that up to the Dark-type Pokemon, and prefer to take the most direct approach by overwhelming the opponent with pure power! One could consider them the "berserker" of Pokemon---their greatest strength can easily be turned around against them if they're not careful!
Beast-type Pokemon are an interesting breed, fitting their nature as berserkers two of the Types they're Super Effective against are also Super Effective against them!
Beasts are powerful Pokemon on-par with Dragon Types, and thus are Super Effective against them. However, this works both ways...Beast-type Pokemon are also weak to Dragon-type Pokemon. When the two Types meet, whoever hits first will likely win!
Beast-type Pokemon are Super Effective against Fairy Types. They don't go easy on "cute" Pokemon, everything is fair game for them. At the same time they are immune to Fairy-type attacks. It may be wise to have Beast and Dragon Pokemon fight alongside one another for this very reason!
Finally, Beast Pokemon hate nothing more than rival Beast Pokemon---and thus this Type is Super Effective against itself. When two Beasts clash, blood will surely fly!
Steel is the worst enemy of the Beast-type, perhaps due to its association with human weapons, and Steel both resists and is Super Effective towards the Beast Type.
Poison is also another element that the Beast Type has learned to fear, and thus Poison is Super Effective against it.
The defensively weak Rock and Ice Types receive a new niche as they resist the Beast Type. Furthermore, Steel would no longer be Super Effective against them!
Finally, the Beast Type does not care for superstitions---and don't really have the brains to be tricked, thus they resist Psychic, Dark, and Ghost-type attacks!
So, to sum it up...
Offensive:
SE: Dragon, Fairy, Beast
NVE: Steel, Rock, and Ice
Defensive:
Resists: Psychic, Dark, and Ghost
Weak: Dragon, Poison, Steel, Beast
Immune: Fairy
One more note...Beast-type Pokemon cannot be infatuated! Love has no place on the battlefield!
A few classic Pokemon would be re-categorized as Beast-type Pokemon...
* Mankey and Primeape, known for their intense anger issues, are now Fighting/Beast!
* Dodrio has always been a difficult Pokemon to deal with! It's now Beast/Flying!
* Tauros have been domesticated in other regions, but their anger still shines through! It's now pure-Beast!
* Mightyena is now Dark/Beast.
* Loudred and Exploud keep their Normal Type, but are now Normal/Beast!
* Zangoose has become pure-Beast! Though it's technically weak to Poison now, Immunity would receive an upgrade---now Pokemon with Immunity cannot be hurt by Poison-type attacks!
* The rival water fish Pokemon, the Basculin, are now Water/Beast!
* Darmanitan in its regular form is now Fire/Beast, becoming Fire/Psychic upon activating its Zen Mode!
* Like Tauros, Bouffalant is now pure-Beast!
* Finally...Komala!? Yes, Komala is considered a pure Beast-type Pokemon! Its savage nature has never been fully known until a researcher managed to wake it---let's just say be thankful it's always napping!
And a few moves would become Beast-type...
* Crush Claw
* Head Charge
* Howl
* Rage (a lot of the Pokemon re-Typed to Beast learn this)
* Razor Wind (Japanese name references the "sickle weasel" Yokai)
* Roar
* Thrash (same reason as Rage, and the deciding factor for a lot of re-Typed Pokemon)
* Uproar