Some utility moves that I think are interesting. With our bias still up in the air, some of my statements here are more conditional than anything; nevertheless, I would like to see where the community stands on these options.
Knock Off: Right off the bat, I will say that if we end up going with a physical bias, Knock Off becomes a strong enough damaging option that it should be rejected. However, on a specially biased build, Pokemon such as Darkrai, Walking Wake, as well as the bulkier Shox provide an interesting blueprint for making it work as utility. However, I still think Knock Off should not be allowed here or at least be burdened with a significant penalty. First of all, it's a universal utility option that can always output value, which is a bit different from Eternatus’ own more limited functionality. It does solve a lot of the concerns about defensive sets in one go. That is not my biggest concern, though. spammernoob, I think, brought up that Knock Off encourages a playstyle with Heavy-Duty Boots and heavy switching, which plays quite differently mechanically from Eternatus’ own best functioning in staying in with some of its sets. One of our goals here is to enable a wider variety of items on sets, which unfortunately I think Knock Off takes us further away from by disproportionately rewarding the Boots set in a hazards-heavy metagame. One way I think this can be built around is by making the defensive 2A + Knock sets low-powered enough that even with Boots they are not always preferred. This seems like a difficult balance to strike, on top of the possibility of some weird admixture set emerging. Like Eternatus, we also have tools against anti-longevity (Toxic immunity in Eternatus’ case, blanket immunity to status and stat drops in ours), so I think it’s worthwhile to explore the option of building up there rather than solving a lot of issues with good ol’ Knock Off.
Trick: Now this might not be powerful enough to merit anything more than a minor consideration, but Choice items and Black Sludge are items we can run to some level of viability, and this move might see use with those (as seen in the examples of

,

for Choice, and

for Black Sludge). Much like how OG Eternatus is forced to run Eject Pack + Draco Meteor as its only pivoting option, I think it would be nice to translate that aspect of unconventional execution over to the task of item removal. The jank set lover in me also hopes for something like itemless Trick after a Meteor Beam or something emerging as a viable set, but even I have to admit that is completely ass. In any case, there is at least some viable angle to it, so I’d like this to be addressed… or automatically accepted as optional or denied.
Mortal Spin: This is putting 38 right back in the hazards game, which is a huge role-defining decision. However, there are some interesting angles here, especially with how the move helps the defensive sets while still maintaining Eternatus’ identity of spreading poison. The first consideration I would want is that we should also allow Steel-types to become reliable spinblockers to it, lest we somehow introduce a really good spinner in the tier when Eternatus is not a spinner at all. My head is at denying Fire-coverage completely in a “Choose One” way if we do allow Mortal Spin, leaving Corviknight and Equilibra as decent enough blockers (the latter is impacted if we go physical, with neutral Grass STAB). I think an additional consideration for bulk could also be merited here, as in with a small penalty to not make the defensive spinner set too valuable. That might be a bit of polljumping, I admit, but this is a move that I nevertheless think should be considered for the Defining list.
Salt Cure: Let us steal Garganacl’s whole schtick while we’re at it, eh? But in all seriousness, I think while it solves a lot of the defensive sets’ viability concerns, it is too centralizing to be a healthy option given our aim of multiple viable sets. Curious to see if anyone has anything to say to the contrary, though.
Will-O-Wisp: I support it, but I’m not sure what the penalties for it would look like. Also, it would be funny to make the third Burn spreading CAP in a row.
Taunt/Encore: Taunt I think has some non-broken use case but is still pretty universally strong, a hard “no” for Encore. Please.