My Metagame

[JustAWalrus]

So I play a grixis deck that revolves around {young pyromancer} and the new {spellheart chimera} I have a long running fued with {aetherling} too. My metagame has a lot of UWR and Esper Control decks that are hard to deal with and mono white decks that I can easily handle. There are some other decks I can deal with but the biggest problem is a GW deck that involves turn 4 {trosani, selesnya's voice} and turn 5 {advent of the worm} then {wake the reflections} and i just cant handle that. Any suggestions on what cards i can run for grixis post rotation, i have {pithing needle} {slaughter games} and {aetherize} so far.

[Gorzo]

It sounds like leaning more into the blue aspect of your Grixis colors for your sideboard might hold the best answers for your problems.

The most efficient way to defeat an ætherling problem only costs 2 mana. {Essence Scatter}. Get rid of it before it hits the battlefield, and you're golden. If other, non-creature spells in those esper control decks are giving you trouble, too, an upgrade to {Cancel} might be better, even though it's much more of a burden to leave {1}{U}{U} than just {1}{U}.

As for the populate deck, I think you're on the right path with {Ætherize}. Bounce is super cheap permanent removal against tokens. I recommend plain old {Unsummon}. At instant speed, it allows you to bounce away his scary token as he casts a populate spell or activates Trostani's ability. For one mana. He wasted mana/populate spells, you remove a threat.

[Agrus Kos, Enforcer of Truth]

If you are having problems with tokens, I recommend {Legion Loyalist} (makes it so tokens can't block when you have battalion) and definitely {Ratchet Bomb}; you drop it for {2}, {T} and sac it and it destroys all tokens (because they have a CMC of {0})

[Mlerner12]

What Gorzo said- add blue into the sideboard! I'd recommend {Cancel}, {Essence Scatter}, and {Counterflux}, along with some bounce, and maybe even an {Omnisciende} or stuff. {Worldfire}, too, If you have enough stuff like {Legion Loyalist}.

[Gorzo]

If you are having problems with tokens, I recommend {Legion Loyalist} (makes it so tokens can't block when you have battalion) and definitely {Ratchet Bomb}; you drop it for {2}, {T} and sac it and it destroys all tokens (because they have a CMC of {0})

I forgot about these two! Also very good suggestions!