DRAGONITE
Dragonite: Not found in the wild
Dragonair: Casseroya Lake
Dratini: Casseroya Lake, North Province (Area One), North Province (Area Two), South Province (Area Six)
HYDREIGON
Hydreigon: Not found in the wild
Zweilous: North Province (Area One), North Province (Area Two), North Province (Area Three), East Province (Area One), East Province (Area Three), South Province (Area One), South Province (Area Six), West Province (Area One), West Province (Area Two), West Province (Area Three), The Great Crater of Paldea, Glaseado Mountain.
Deino: North Province (Area One), North Province (Area Two), North Province (Area Three), East Province (Area One), East Province (Area Three), South Province (Area One), South Province (Area Six), West Province (Area One), West Province (Area Two), West Province (Area Three), Glaseado Mountain
BAXCALIBUR
Baxcalibur: Not found in the wild
Arctibax: North Province (Area Three)
Frigibax: Dalizapa Passage, Glaseado Mountain
GARCHOMP
Garchomp: Great Crater of Paldea (after defeating every titain)
Gabite: North Province (Area One), North Province (Area Two), North Province (Area Three), East Province (Area One), East Province (Area Three), South Province (Area One), South Province (Area Six), West Province (Area One), West Province (Area Two), West Province (Area Three), The Great Crater of Paldea, Glaseado Mountain
Gible: North Province (Area One), North Province (Area Two), North Province (Area Three), East Province (Area One), East Province (Area Three), South Province (Area One), South Province (Area Six), West Province (Area One), West Province (Area Two), West Province (Area Three), The Great Crater of Paldea, Glaseado Mountain
GOODRA
Goodra: Not found in the wild
Sligoo: Casseroya Lake
Goomy: Tagtree Thicket, Casseroya Lake, North Province (Area One), North Province (Area Two), East Province (Area Three), South Province (Area One), South Province (Area Four), South Province (Area Five), South Province (Area Six), West Province (Area Three), Glaseado Mountain
DLC EXCLUSIVE ————————
METAGROSS (Indigo disk)
Metagross: Not found in the wild
Metang: Polar Biome (Lower half)
Beldum: Polar Biome (Lower half)
KOMMO-O (Kitakami)
Kommo-o: Not found in the wild
Hakamo-o: Oni Mountain
Jangmo-o: Paradise Barrens in the northwest of Kitakami
*NOTES: Some Pokemon like Hakamo-o, Deino, Zweilous and Frigibax are found in caves I believe. I did not include the violet-exclusive Pokemon because you asked for Pokemon scarlet and I did not include Tyranitar seeing how you already have one. All of these Pokemon pre-evolutions evolve via level up. Some final evolutions are found in tera raid battles and static encounters (not listed, easily found online no worries ;)))*
Sources:
This website
Dexerto.com
Twinfinite.com
Gampur.com
Mr. Fish
Lemme know if I missed anything and I hope I helped! :)