A simple question that can be answered with facts and logic.

>Megas
Kanto: 15
Johto: 6
Hoenn: 20
Sinnoh: 5
Unova: 1
Kalos: 1+(1)Greninja Ash*
Alola: 0
Galar: 0
>Regional Forms
Kanto: 29
Johto: 2
Hoenn: 2
Sinnoh: 0
Unova: 5
Kalos: 0
Alola: 0
Galar: 0
>Cross-gen evos/pre
Kanto: 34
Johto: 13
Hoenn: 8
Sinnoh: 0
Unova: 1
Kalos: 0
Alola: 0
Galar: 0
>Z-Moves
Kanto: 6
Johto: 0
Hoenn: 0
Sinnoh: 0
Unova: 0
Kalos: 0
Alola: 11
Galar: 0
>G-Max
Kanto: 12
Johto: 0
Hoenn: 0
Sinnoh: 0
Unova: 1
Kalos: 0
Alola: 1
Galar: 18

So in total it is:
Kanto: 96
Johto: 21
Hoenn: 30
Sinnoh: 5
Unova: 8
Kalos: 2
Alola: 12
Galar: 18

The winners are: Kanto(96), Hoenn(30) and Johto(21)
The losers are: Unova(8), Sinnoh(5) and Kalos(2)