They don't go away as steps, phases, and turns end, and effects that add mana "of any type" can't give you energy counters
You could wind up not getting much mana out of it, but youll probably get a lot of it if youre using Klauth, Unrivaled Ancient with a bunch of other mid-to-big dragons
Time will tell if Duskmourn: House of Horror is the success many are predicting it will be
Like, for example, on Dont Blink
Why bother speeding out three- and four-drops when the power level of the one- and two-drops themselves have increased so dramatically (Ragavan, DRC, Ledger Shredder)
If you've ever sat in the grass and bathed in the sun's warmth and the smells of the flowers, you can experience this with much more than your eyes