1. From time to time, they sell fragments from past fusions. In addition to that, you can pull Hoskarul from a shard like any other epic.

2. You get a bit more energy. Start 130. One energy pack for 5 arena battles (260). One energy pack from doing all advanced quests (390). 50 energy for advanced arena quest (440). One energy pack for 1h playing (570).

More energy can be obtained from the tag team arena bazar, clanshop, tournament rewards. 

In addition to that, you can buy energy for gems in the shop. One energy pack is at 40 gems. You get gems for free from the mine, quests, tournament rewards.

And there are parts of the game that don't require energy at all. Classic Arena, Tag Team, Faction Wars, Clanboss, Doom Tower.

For spending your energy, you have to find a balance between farming campaign (get more champs to lvl 60), farming dungeons (get better gear), farming minotaur and potion keeps. 

I still only at 115 energy cap, but that's not too significant. The most problematic for me is advanced quests, since it either has a "beat up a faction war boss" or "use 5 silver keys in DT" quest, which I am unable to do yet. Hence was the question, which approach do you use: all in for 1 thing a day, or do a little from everything every day.

As for the fragments, thank you, now I know I should watch out for fragments in the clan shop(I guess)

Don't forget to horde the refills from the daily login packs (appreciatin, goody bag, etc.).  They drop 3 times a week.  I believe on Tuesday, Thursday, and Sunday

Well, I try to get as many daily, advanced, etc., done as I can.  Then I typically use the rest for one thing.  If there is a Tourny or event I'm interested in then that.  sometimes I stock up on potions.  Otherwise I work on scrolls.

Fragments: no, sadly in the shop for real money only. I sit on 95 fragments for Clanfather Opardin by myself. 😢

For the spending of energy: In the end, you have to do all things I mentioned.

First, farm food-champs in campaign to rank up a new champ to 6*. After doing so, run potion keeps to ascend your new 6* champ. Now, run Minotaur with your new champ to give him masteries. And at last, run Dungeons to get equip for your new champ.

As the potion keeps only open on certain days during the week, once you planed who should be your next 6* champ, you can run the fitting keep allready.