Prior to Duviri, I put in some time acid testing boilerplate builds to get all my frames to scale into SP Circuit. I’ll summarise the work here. I’m happy to answer any questions in the comments. Hopefully this will be of some use!
As a bonus, none of these require energy->shield mods or Decaying key, although using either or both adds an extra layer of survivability.
Infinite Scaling
Condemn helminth! Easily the comfiest and most reliable way of shield gating, as it CCs enemies and shield gates most frames in just two or three targets affected. The ability has a “soft” slam animation that has reduced priority over double jump and parkour, so casting during a double jump or bullet jump will keep you airborne. It’s also a one-handed cast so does not interrupt reloads, and you can shoot mid-cast.
The important requirement is that you need to compensate range or strength on Overextended or Narrow Minded builds, or use the next helminth option.
Pillage helminth. Unlike Condemn, provides absolutely no CC, so I only recommend this on frames that have some kind of innate CC such as a slow, distraction, confusion, etc. Also a full-body cast so it prevents movement and other actions, and comes in at twice the casting cost.
Infested
The heck faction… until now. Silence helminth completely reduces them to melee, which should not be a problem with Warframe movement. Just don’t get in a slap fight with any Disruptors or Toxic Ancients (or Venomous Eximus).
Silence prevents grapple hooks and Osprey clouds, as well as all Eximus casts. The only remaining mechanics are the Ancient stretch arm attack and MOA goop and clouds, but the MOA attacks do fixed low damage, so no biggy.
I just want to face tank to level 300
Health Conversion from Simaris, Arcane Blessing from Conjunction Survival, and your choice of Fractured Blast (same build constraints as Condemn) from Citrine, or Lycath’s Hunt from Voruna (preferably don’t dump stat Duration). Frames with inbuilt DR can go quite a bit farther than that, but even Banshee or Gyre can facetank with HCAB strats.
But I’m Inaros or Lavos
This section is theoretical, since I don’t have Trickery.
Desiccate, Ophidian Bite, and Dagger heavy attacks force finishers, so you could use this with Arcane Trickery to stay invis. Otherwise possible helminths are Resonator (from Octavia), or Shooting Gallery (from Mesa) + Muzzle Flash augment.
To note:
Revenant and Zephyr can both survive using their unique abilities to any level. Zephyr has a harder time of it and they both need casting speed for real safety, but they both can do it (plus Zephyr gets all her other cool tricks, CC, and damage spreading tornadoes). Garuda can also get away with spamming her 4 for invincibility (and 3 for energy) using Molt Reconstruct + shield-gating, and of course there are invisibility frames. Loki with Safeguard Switch is nearly as invincible as Revenant and any invisibility frame (Voruna, Ivara, Ash, Octavia) with rolling guard can survive pretty well even when allies are getting enemies to fire straight at you (at least long enough to reposition out of harm’s way or kill the enemies).
If you want to facetank, slotting in adaptation is extremely useful, in addition to Arcane Blessing and Arcane Double Back. Healing is important, though, so I also recommend subsuming gloom, which is the ultimate subsume for HP tanking since it provides tons of CC in addition to lifesteal, and there really isn’t any better source of super-consistent healing for most frames. You can get to level 900+ with all of this, especially once you add in umbral mods.
I would also note that Revenant is the ultimate facetanker, but doesn’t use HP for it (Mesmer Skin is my favorite ability in the game because it lets me chill even in Steel Path). All he needs is casting speed (recasting Mesmer Skin leaves you temporarily vulnerable and is slow enough that a shield-gate won’t necessarily keep you alive, but casting speed will fix that), energy (he’s not energy-hungry as long as you don’t slot in blind rage and don’t use his 4 (though there are builds that work with his 4 rather than abandon it)), and ability strength (though even unranked and with no strength mods Mesmer Skin can keep you alive better than a normal shield-gate build provided casting speed). As a word of warning, a few rare things (mostly barrels/environmental damage) do bypass Mesmer Skin, but Mesmer Skin will keep you alive regardless because you literally cannot go below 2 HP with Mesmer Skin active (though you will assuredly die when you attempt to recast it if you don’t have your shield up).
As always, though, the best method of defense is offense. You’re going to have trouble taking damage if you just stand still, no matter how much EHP you get. It’s important to have weapons that can clear rooms in seconds in Steel Path because you will only have seconds to clear before you die or have to bother with surviving in some way (like refreshing your shield).