Should you pull Ramona?
Should You Pull? (TLDR):
It depends on if you have Tuesday (then yes) or not (then no).
Do you like Poison?
Gameplay and Review
Gameplay
Ramona does one thing and does it very well: Supercharge Poison.
Everything in her kit is dedicated to making Poison explode for maximum damage. Of course, she’ll still need Tuesday to meet her full potential (as has been the trend since 2.1) but overall Ramona makes the team exceedingly powerful, to the point that they’ve killed Mane’s Bulletin bosses (100M HP).
So, how does she do it?
Poison itself is simple. Apply stacks, and have Tuesday around to allow the debuff to Crit and stick around with her Array. Ramona then adds the damage to exploit these effects.
Her insights revolve mostly around applying Poison, stacking [Exorcist-For-Hire] and cycling Moxie for her Ultimate. One interesting point is that at the start of the round, [Exorcist-For-Hire] stacks are consumed to apply [Possessed] to cards in hand.
Let’s start with her Ultimate, “Return Peaceful Slumber to Both Worlds” is a mass debuff that converts several stacks of Poison into [Expellant], which is a more powerful version of [Poison] that stacks a continuous DMG Bonus for itself and still counts as [Poison].
Her skills aren’t all that interesting. “Purifying Incense” is a mass debuff that inflicts [Poison] and stacks [Exorcist-For-Hire].
“Ghost-Be-Gone” is a 1-target debuff that also inflicts [Poison] and immediately resolves all stacks of [Poison] once.
There is an extra Incantation that can be generated through casting [Possessed] incantations. “Marigold Method” is a mass debuff that inflicts [Poison], but also [Spirit Repellent] which is a stacking debuff that resolves [Poison] per round for every stack.
The combination of consistently more powerful [Expellant], a consistent application of [Poison] and being able to resolve [Poison] several times per round makes her a perfect fit for the team.
Review
Honestly the review doesn’t have to be that long, because the only really relevant part is that the Poison Team is now capable of quite literally killing a Mane’s Bulletin boss (which is intended to be an infinite mode). She does a lot of damage, and with the usual suspect (Tuesday) she does even more damage. It's really quite simple.
The team itself does change, however. Because of her Euphoria, Willow actually moves over to the Sub Carry category. She no longer requires much AP, and while she is still always casting, Tuesday’s Euphoria also allows the two to work in tandem to push Ramona into the Damage Dealer role.
But that’s not the only option, because Willow still has one problem. She is entirely single-target, and the moment two opponents appear, Willow actually gets traded out for Ezio Auditore (or Jessica, in case you don’t have the collab character). Ezio is here entirely for a very specific weapon combo (3-3) that allows [Poison] to bounce between units upon kill, which bypasses the single-target nature of the archetype.
Extremely consistent and high [Poison] application.
Able to resolve [Poison] more times per round than anyone.
Very consistent Moxie cycle that allows for constant ramp.
Like the rest of Poison, tied to the hip to Tuesday.
Most effective AoE set-up requires a collab character.
Portrait, Synergies, Psychubes and Resonance
Portrait
Ramona is complete at Portrait 0.
Slight vertical investment is recommended to open up her teambuilding.
Portrait 1 improves her Moxie cycling and boosts her [Poison] and [Spirit Repellent] application, which is the core of her character.
Great Synergies:
Ramona is a Poison Damage Dealer, and mostly tied to the hip to her archetype (and certainly Tuesday).
Core:
Tuesday Poison:
Willow , 
Ezio Auditore , 
Jessica Other:
Flutterpage
Psychubes:
Falling for a Sweet Phenomenon 
Drown Out The Hustle
Falling for a Sweet Phenomenon (37 Anecdote): The increased Genesis DMG Dealt stacking with Extra Actions (which Ramona has a fair bit of) is easy to proc powerful extra stacks.
Drown Out The Hustle (Ramona Sig): Very powerful stats with extra Genesis DMG Bonus and Poison DMG Bonus, however the stacks are less potent than 37’s Anecdote and take more time to stack up fully.
Resonances:
Code - APQkOAU4RStENFI0UCgxQAQrAz8CPRBDAEYh
Recommended Pattern is Aspirational
Team:
Poison is a very simple Archetype: Cycle Tuesday’s Array, cast everything that inflicts Poison, resolve Poison as many times as possible.
The two main drivers for Poison application are Ramona and Tuesday, with Tuesday at its core (of course). Willow is primarily used to convert stacks into [Hag’s Bane]. The excessive application is required since Willow and Ramona both convert the debuff into separate debuffs.
Ramona is here to resolve Poison over five times a round. Tuesday is here to make the Poison stick around utilizing her Array, and those two form the most important link in the team.
Willow can be utilized in 1-target situations due to her powerful ST application and output through her conversion. Ezio Auditore is used with the 3-3 weapon combo to allow all the stacks of poison to bounce between targets upon death and thus deal damage in an AoE.
The sustain is pretty flexible, the one important thing is that they don’t consume any AP, so Marsha is the likeliest pick (she also inflicts some debuffs that can trigger Tuesday).