lvl 26 High Resolution Dragon A+ rank(finished 1st on the high resolution race also was the 1st heroic dragon I got)
lvl 25 High Amuka/Fighter Dragon A+ rank(high score race but finished on about 2nd place and not reached lap 15 but still reached at least lap 12)
lvl 25 High Feral Dragon about C+ rank(high feral alliance race my team finished 1st and if I remember my team was the only who qualified or there were more team that qualified, I don't really remember that well)
lvl 23 High Fallen Dragon C rank(finished on 1st place on the High Fallen race)
lvl 27 Supersonic Dragon A+ rank(breeding via breeding sanctuary)
lvl 25 Apocalypse Dragon A+ rank(same as for the Supersonic Dragon)
lvl 25 Abyssal Dragon about between B- and B+ rank(same as the 2 previously named dragon)
lvl 22 Pure Flame Dragon A+ rank(breeding)
lvl 20 Pure Terra Dragon A+ rank(breeding)
lvl 20 Double Terra Dragon A+ rank(the only cat 4 dragon I have ranked to A+)(If I remember I got from a calendary mini event)
lvl 23 Gummy Dragon A rank(one of the 2 cat 3 dragons I manage to rank to at least A- rank)(breeding)
lvl 20 Volcano Dragon A- rank and empowered with 4 stars(the only on my list who's empowered the other dragons I haven't empowered yet and are on 0 stars since also I don't own the enough amount of orbs to empower some of the named)(breeding)
lvl 20 Dujur Dragon B- rank(breeding via breeding sanctuary)
Without counting heroics would be
(Normally)Light: Apocalypse Dragon(sometimes other element attacks)
(Normally)Electric: Supersonic Dragon(sometimes other element attacks)
(Normally)Dark: Abyssal Dragon(also sometimes other element attacks)
Pure: Pure Terra Dragon
Normally fire but sometimes pure: Pure Flame Dragon
War: Millenium Dragon(sometimes the other element attacks)
Metal: Silly Dragon(sometimes other element attacks)
Terra: sometimes Pure Terra but also sometimes Double Terra Dragon
But it's not always the case it's normally a very usually, sometimes I use others like Night Forest Dragon, Volcano Dragon, Gummy Dragon, Dark jester Dragon, Boulder Dragon and etc...
High Feral Dragon(which was the 3rd heroic I got): It does look amazing and it would on a tie with the High Supremacy Dragon(which I don't even have)
Supersonic Dragon: probably one of my first legendary(in rarity not in element) dragons that I got, still it's very solid.
High Resolution Dragon: The first heroic I got, looks amazing, very retro game themed and would be in a tie with the High Score Dragon(also I don't have because I didn't reach lap 15 on the High Score race and didn't end on 1st place but still I got the High Amuka since I reached at least lap 12 on that race).
Silly Dragon: looks very funny
Pure Flame Dragon: I do remember yet the days when pure had no weaknesses and I remember that I got my Pure Flame Dragon(back between mid 2015 or mid 2016) by breeding Ivory or Pure Terra(which I got if I remember by breeding Ivory Dragon(which I got from free cards back in 2015 on the pc version of Dragon City and I could get some pures because they weren't locked during that time) with a Terra Dragon) with a flame dragon.
Quite P2W compared to Monster Legends cells donation because you need something also if you want to trade that depends on the rarity of the orbs you're asking, plus you'll need other orbs of the same rarity as the orbs you ask, today I asked for kitsune dragon orbs in exchange for giving boulder dragon orbs( since I already own one boulder dragon) which those dragons are legendaries, but I don't have any problem, it's a neutral opinion.