Oh, quite a choice of dragon types!
Dragonite- Prominent in Lance's teams, in Fiore there's a dragonite transporting Rangers of a certain grade from a Ranger base to an other. Sis seems to have a thing for the dragonite family.
Salamence- Was quite a nasty competitive pokémon and still is. Reminds me of the bagon seen at the golden caves of the Meteora falls(note : it was on sapphire). Sister also does, have a thing for bagon (and possiblly the evolutions)
Garchomp- Part of Cynthia's team and many other trainers seen in the Sinnoh victory road. Used back in gen4 as competitive as well as legendary buster(can learn false swipe), still prominent in competitive, part of Se Jun's Team at the VGC championship of ANNO DOMINI 2014. In the 18 seasons anime one is seen competing with a supersonic jet.
Hydreigon- I have an all particular bias towards gen5, it's the one I call "the missed generation"... back in the day I sticked to diamond and decided not to progress(of course I regret it), I remember seeing the starters, zorua, zoroark, reshiram, zekrom and woobat sprited in flipnotes... there's a hydreigon in Ghetsis' team and one has a major role in Mystery Dungeon: Gates to infinity(and breaks the fourth wall).
Kommo-o- Uhm... they have a legend about protecting Alola, methinks?
Kingdra- One is seen in Claire's team. Two are part of the trials inside the Olive jungle relic in Fiore. Those trials were apparently performed by Rangers in the past. The kingdra family is based off sea dragons and sea horses, which leads to sea horses being part of my mother's childhood, since they were common in the mediterranean decades ago(ironically, the mediterranean looks like a kingdra and mother claims not to be fond of water types overall due to aesthetic tastes).
In the end, I'm choosing kingdra!
Perhaps they can't fly, but still!
Uhm... who am I putting down again...?
How about my "you mysterious entity" team?
1-Pikachu
2-Ditto
3-Marowak
4-Arceus
5-Zoroark
6-Braviary