Dear Members,
I need some inputs on how YOU - player reading this - makes an inform decision on which dragons do you level up to 30+.

With 2K+ dragons and rising....surely each one of us runs out of food.

The only ones I level up to 35 are heroics, Mythicals up to 30. For everything else regular legends to 21, regular VIPs to 24 and everything else to 15. If a different level is needed for a quest, arenas or event that will all depend on what the reward is and what the dragon that needs leveling is. FYI the majority of my empowered dragons do not get leveled past their norms.

That's exactly what I was looking for. Regarding Mythicals, VIP and legendary I'm not clear on how to distinguish them (except Mythicals with their dedicated symbol) As I am not buying dragons with real money my guess is I don't have VIP.

Here are all my legendary dragons. Triumphal and Cryogenic dragons are the only mythical I have. I have read about categories and I guess cyber dragon is bad as Jolly dragon for instance is better with a lower level. It seems to be the same with feral dragon (but his rank is C when black fire is B-). A lot of those legendary dragons have four elements so I was thinking to level up them and let legendary with less elements on lower level.
Did you go each time to dragon city guide to check dragon category before ascending them?

With dragon rescue event, I have collected 18 millions food and I would like to use them properly.

Hi, @AlexMex my answer to your question will be based on my own preference - i level up dragons that will be easily empowered (Legendary dragons) and next is the 4 element criteria.

So, if I were to choose from your picture - I will feed the following top 3 dragons.

1. Thunderbolt - because you already have it 1*
2. Triumphant - because it is Mythical - they can withstand less damage although you will have less chance to empower them if you don't spend money.
3. Topaz - because Social Point has given them away as rewards that you have a chance to empowered them up to 5* (will take you longer though).
4. Breed/Empower/Feed: Apocalype/Abyss - but Millennium/Mirage is better but harder to get.

PS: I still only have a 2-star Millennium. I don't have enough food to focus on breeding Millennium - so I am taking it slow.

I have kooky parameters of my own that I use as rules for leveling things up. Got to prioritize where I put my food and things. These rules only apply to category 9/4 element and higher dragons

If its empowered once or more = 35+

Heroics and Mythics = 35+

If its cat 9 AND has two or more powerful elements (Ie: Pure, War, Legend, Wind, Primal) = 35+ (otherwise 30) This one is sort of last priority... unless I need it absolutely now for an arena

If you have something 5 starred (such as that football they just gave us) you may want to consider raising that, even tho its not cat 9. Im not sure how it will do, so Im on the same fence with that one