Each dragon can be summoned via a command. You can summon a random/default one or you can summon a specific one.
Do not try to summon variants that do not exist. At best it will summon one without a texture at worst it can crash your game.
Random: /summon wyrmroost:overworld_drake ~ ~ ~
Plains male: /summon wyrmroost:overworld_drake ~ ~ ~ {Variant:0,Gender:1}
Plains female: /summon wyrmroost:overworld_drake ~ ~ ~ {Variant:0,Gender:0}
Savannah male: /summon wyrmroost:overworld_drake ~ ~ ~ {Variant:1,Gender:1}
Savannah female: /summon wyrmroost:overworld_drake ~ ~ ~ {Variant:1,Gender:0}
Albino: /summon wyrmroost:overworld_drake ~ ~ ~ {Variant:-1}
Random: /summon wyrmroost:silver_glider
Female: /summon wyrmroost:silver_glider ~ ~ ~ {Variant:0,Gender:0}
Red male: /summon wyrmroost:silver_glider ~ ~ ~ {Variant:0,Gender:1}
Green male: /summon wyrmroost:silver_glider ~ ~ ~ {Variant:1,Gender:1}
Bleu male: /summon wyrmroost:silver_glider ~ ~ ~ {Variant:2,Gender:1}
Golden: /summon wyrmroost:silver_glider ~ ~ ~ {Variant:-1}
Random: /summon wyrmroost:roost_stalker ~ ~ ~
Normal: /summon wyrmroost:roost_stalker ~ ~ ~ {Variant:0}
Albino: /summon wyrmroost:roost_stalker ~ ~ ~ {Variant:-1}
Normal: /summon wyrmroost:lesser_desertwyrm ~ ~ ~
Blue: /summon wyrmroost:butterfly_leviathan ~ ~ ~ {Variant:0}
Purple: /summon wyrmroost:butterfly_leviathan ~ ~ ~ {Variant:1}
Albino: /summon wyrmroost:butterfly_leviathan ~ ~ ~ {Variant:-1}
*in some versions only the comand for the female variants work.
Random: /summon wyrmroost:canari_wyvern ~ ~ ~
Blue male: /summon wyrmroost:canari_wyvern ~ ~ ~ {Variant:0,Gender:1}
Blue female: /summon wyrmroost:canari_wyvern ~ ~ ~ {Variant:0,Gender:0}
Green male: /summon wyrmroost:canari_wyvern ~ ~ ~ {Variant:1,Gender:1}
Green female: /summon wyrmroost:canari_wyvern ~ ~ ~ {Variant:1,Gender:0}
Purple male: /summon wyrmroost:canari_wyvern ~ ~ ~ {Variant:2,Gender:1}
Purple female: /summon wyrmroost:canari_wyvern ~ ~ ~ {Variant:2,Gender:0}
Red male: /summon wyrmroost:canari_wyvern ~ ~ ~ {Variant:3,Gender:1}
Red female: /summon wyrmroost:canari_wyvern ~ ~ ~ {Variant:3,Gender:0}
Yellow male: /summon wyrmroost:canari_wyvern ~ ~ ~ {Variant:4,Gender:1}
Yellow female: /summon wyrmroost:canari_wyvern ~ ~ ~ {Variant:4,Gender:0}
Random: /summon wyrmroost:dragon_fruit_drake ~ ~ ~
Baby: /summon wyrmroost:dragon_fruit_drake ~ ~ ~ {Age:-12000}
Male:/summon wyrmroost:dragon_fruit_drake ~ ~ ~ {Variant:0,Gender:1}
Female:/summon wyrmroost:dragon_fruit_drake ~ ~ ~ {Variant:0,Gender:0}
Golden: /summon wyrmroost:dragon_fruit_drake ~ ~ ~ {Variant:-1}
Random: /summon wyrmroost:coin_dragon ~ ~ ~
Red: /summon wyrmroost:coin_dragon ~ ~ ~ {Variant:0}
Blue: /summon wyrmroost:coin_dragon ~ ~ ~ {Variant:1}
Yellow: /summon wyrmroost:coin_dragon ~ ~ ~ {Variant:2}
Grey: /summon wyrmroost:coin_dragon ~ ~ ~ {Variant:3}
Green: /summon wyrmroost:coin_dragon ~ ~ ~ {Variant:4}
Random: /summon wyrmroost:royal_red ~ ~ ~
Male: /summon wyrmroost:royal_red ~ ~ ~ {Variant:0,Gender:1}
Female: /summon wyrmroost:royal_red ~ ~ ~ {Variant:0,Gender:0}
Melanistic: /summon wyrmroost:royal_red ~ ~ ~ {Variant:-1}
Commands for the versions of the mod where it was genderless
Random: /summon wyrmroost:alpine ~ ~ ~
Blue: /summon wyrmroost:alpine ~ ~ ~ {Variant:0}
Black: /summon wyrmroost:alpine ~ ~ ~ {Variant:1}
Yellow: /summon wyrmroost:alpine ~ ~ ~ {Variant:2}
Green: /summon wyrmroost:alpine ~ ~ ~ {Variant:3}
Red: /summon wyrmroost:alpine ~ ~ ~ {Variant:4}
White: /summon wyrmroost:alpine ~ ~ ~ {Variant:5}