Mardu Ephemerate (Pauper)

This wants to be a non blue control, with a combo/beat down strategy. Not having access to blue, this uses remuvals (in main) and discards (in side) to control: BR have access to the best remuvals in the format: terminate is the best single target remuval, and cast down follows closely, galvanic blast is just too good to remove little to medium threats and to close the game. As for the draw, I opted for the new White draw package: spirited companion is a great good boy, and inspiring overseer is huge.; other draw engine are cleansing wildfire, that allows to ramp, the blood token from the blood fountains, and the monarch from the commodore, which defends and can get back the monarch preatty easily. To end the game we have two options: the bleak coven vampires and ephemerate combo to drain a lot from the opponent or the soul of migration and ephemerate to get a lot of flying tokens: either way, we could swing for 12 hp drain with the vampires or get 6 flying 1/1 (3 ETB) which is huge. At last, both ardent elementalist and blood fountain allows the recursion from the graveyard, so in case of grinding match-up, we could get the upper hand thanks to these.

As for the sideboard, my suggestions are:
3x of fiery cannonade: this is the only decent board swipe and even if kills most of the stuff we play, the important threats remain on board. In alternative to this, also suffocating fumes and electrickery are a reasonable options
2x Leave no trace: this is just istant win against boogles and also can help in various situations, such as oblivion ring or journey to nowhere.
6x of discards: there are some good spells in pauper that can help: one is duress, great against other midrange or control decks; raven's crime, a little less powerfull but with the option of retrace can transform a bad topdeck in a good trade and last but not least castigate, which for 2 mana we can remove for good a big threats for the opponent.
2x graveyard hate: I think that 2x of bojuka bog in main could be already enough, but better be safe than sorry. The graveyard hate needs to be opponent specific, because we wants to use our graveyard recursions, so relic of progenitus is not a good card here, and we could probably prefer a tormod's crypt or a nihil spellbomb.
2x blue hate: this could be either pyroblast or red elemental blast. Blue-based controls are our nemesis so these, other than the discard package, are our only way to fight on equal ground.

OTHER CARDS THAT COULD BE GOOD

Dawnbringer cleric has a really strong etb, very versatile so could be put in instead of 2x discards in the sideboard
Late to dinner could be good if the opponents does not play graveyard hate. Also this could be traded for 2x of discards in the sideboard
Patrician's scorn could be used instead fo leave no trace. To my experience these 2 cards are interchangeable without any adjustment, just play the one you like most.
Dust to dust is a great card if in your meta there are a lot of affinity, jeskai ephemerate or grixis ephemerate. Otherway is just skippable.
Chainer's edict, as any other sacrifice effect, it is great against boogles, not so much in an aggro mu.
Omen of the dead, if you want more recursions with the graveyard, but we already have blood fountain which could be enough
Carrion Locust: if you need better grave hate, this is quite good with ephemerate
Destroy Evil: good side card, can deal against big threats or ench, very nice