A take on the Hardened scales deck of old but with new toys like Esper Sentinel, Power Depot, Zabaz, the Glimmerwasp and the big bad in the room Urza's Saga.
For the most part lists I've seen have 24 Creatures, 8 Utility Artifacts, 8(4) Enchantments, and 20(24) lands - the () are depending on how you classify Urza's Saga.
But, there are a few things I feel iffy on. Such as, do I play Arcbound Mouser or Arcbound Worker and how many. My reasoning here is because of the amount of pain lands that can be run like Horizon Canopy and Spire of Industry. Also, I am thinking about how many Esper Sentinels and Steel Overseer I should play. In my past experience with previous iterations of the Scales decks Steel Overseer was a good target for removal instead of a Arcbound Ravager or Walking Ballista. And without Ancient Stirrings the card draw from Esper Sentinel could be worthwhile.
I'm also just unsure about the correct utility artifacts to run. Most of the other lists I've seen have 8 slots for non-creature artifact spells. With a standard 3 The Ozolith, and at least 1 Welding Jar. With a minimum number of games so far with Basilisk Collar and it was fantastic to just ping down creatures with Walking Ballista. But this leaves 3 open spots to play with. I've been between cards like Throne of Geth to mess with opponents sagas, or something like Aether Vial or possibly a Blast Zone to save my creatures. Plus its great to just make my things bigger as well. Also, Animation Module to keep creatures coming onto the battle field and to also proliferate a single permanent in a similar fashion as Throne of Geth, and some new tech with Power Conduit to continuously keep Urza's Saga at 2 counters and fetch out something every turn. There are also a few lists that run a bunch of 1 of utility spells like Springleaf Drum, Shadowspear, Pithing Needle
Now for lands... 20 seems like the correct amount and 4 Inkmoth Nexus is a must. I've also chosen to go with at least 2 Branchloft Pathway
, and at least 2 copies of Horizon Canopy for more white sources. Other lists I've seen have played 4 Horizon Canopy and 4 Razorverge Thicket, which sucks later in the game, but I can always choose Green or White, whereas with Branchloft Pathway
you're forced to choose. However, due to Zabaz, the Glimmerwasp, I feel the need to run lands such as Power Depot and Spire of Industry to produce the Red needed. So I dont feel like I can run 4 of all of the GW lands. I also continue to find that Llanowar Reborn is good every time I play it, as I get to freely move the counter, unlike Power Depot. But, I can proliferate the counters on both lands later in the game. Also they both come in tapped so that sucks, but only it's terrible on T1 if you have a scales in hand and no other 1 drop creature because then you're waiting until T3 to play a threat. I have also won a couple matches because of Gavony Township, but is definitely not an optimal card to play in modern.
Sideboard Time.... Its whatever you want in my experience. Lurrus of the Dream-Den is good for grindy games as you can cast a ton of things from the graveyard. I bring a decent amount of graveyard interaction like Tormod's Crypt, Soul-Guide Lanturn, Grafdigger's Cage, and Relic of Progenitus because my local meta's use a lot of it. Nature's Claim is a life saver against things like Rest in Peace and Blood Moon, or other artifact hate cards. I also still play against Tron often so I bring a few copies of Damping Sphere and Void Mirror is a very nice new card from MH2 to also help. I also like the addition of Path to Exile now because of the white mana, but Dismember is still good here. Prismatic Ending is also pretty good too, because of Spire of Industry to make other colors, and it doesn't let them fetch. You can also bring things like Pithing Needle and Shadowspear as well to get them out with the 3rd part of Urza's Saga.
I'm a big proponent of just making your sideboard what you need for your local meta, there will always be people playing T1 decks, but also people will just show up with random pet decks like UG Infect, Boggles, Ponza, or Drege. So keep your LGS meta in mind and bring some crazy sideboard tech.