Ever since it was revealed that Cooler-Frieza’s brother had a 5th form, fans have speculated as to whether Frieza also possessed one.
Technically, Golden Frieza is his final form now but prior to this the impression was that he’d have a brand new form like his brother instead of simply a recoloring.
And this is the story followed in “Dragon Ball Multiverse Universe 8,” and in this variation of events.. Frieza wins his fight against Goku… and never becomes Golden Frieza. However in the multiverse tournament, Vegeta encounters a Tsuful in battle capable of recreating people’s energy, who recreates Frieza and his family. Vegeta in Super Saiyan 2 form is able to take out King Cold, which prompts Frieza and his brother to unlock their final forms..
They’re both defeated though.
Moving onto Frieza’s clan and their forms, all of their earlier forms are meant to surprisingly suppress their full power in order to control it better, they’re actually born into their “final forms.” Prior to Frieza training in order to become Golden Frieza, he’d never needed to train before in his life. In fact he was born so powerful that as counterproductive as it may seem, all his other forms were meant to suppress his power or were seen as a regression of his true strength, his 1st form isn’t his base form!
Cooler never stuck to this same concept because he wasn’t a part of the main series, aka non canon. For Frieza though, the key to strength never was in larger physical transformations, but rather a simple recoloring.