Oh this looks like a tough one, since alot of the good ones you have are gonna require either skill or investment to get the most out of their abillities.
My top pick would probably be Silent Kill, as her access to both BUFF removal and DEBUFF cleansing makes her very versatile agaisnt alot of pesky modifiers and BUFF heavy fighters in general. You also seem to have her leveled up abit, so that also saves on investment and resources. Her biggest weakness however is her low attack, which will make her struggle against opponents with high health/or defence, though if you already have a good damage dealer from one of the other tiers, you can instead rely on them for damage output while Silent Kill deals with any pesky BUFF or DEBUFF effects.
A fighter who can also help greatly with damage output is Hack n' Splash, as her access to both PRECISION and ARMOR BREAK allows her to do great damage when paired with Ms. Fortune's kit. That being said you will need to practice landing well timed blocks to activate her abillities, but if you don't mind that then she's probably the best picks in terms of raw offence.
° Her secondary abillity also gives additional damage output through Ms. Fortune's Headless gameplay, so if you can manage that aspect of her abillities then she can be even more potent on offence.
High Ruler is also a really good offensive variant, however instead of damage output, she instead gains access to very powerful DEBUFFS that can completely shut down the opponent, of which include DISABLE BLOCKBUSTERS (meter control), CURSE (BUFF prevention), and HEX (disables the opponents abillity). She does come with a skill ceiling however, as you'll need to learn how to use Parasoul's tears effectively in order for these effects to be inflicted, so I can't really recommend her unless you have good experience with Parasouls kit. Regardless, she's very awesome and probably one of the best gold Parasouls, so do at least keep her in mind if you decide to skip her.
° Parasouls kit allows for great damage output through CRITICAL hits, though you'll need to invest in both CRITICAL MASS (her Marquee abillity) and additional Crit rate through Special Moves and Blockbusters. CRITICAL THINKING can also work if you invest in Crit damage instead, though is generally less recommended.
Honorable Mentions:
Moonstruck has really great BLOCKBUSTER METER control, along with some good damage output with her high attack and easy access to STAR meter. I'd honestly rank her with Silent Kill, as she's just generally good and easy to use on offence, however if you don't have access to any of Annie's multi-hit projectile BLOCKBUSTERS - Sagan Beam & Millennium Cyclone - then you may want to hold off on her until you get either of those.
Persona Assistant is a jack of all trades, working on offence, defence, and as a support, allwhile excelling at none of these roles. While not the greatest variant, she is still pretty helpful on offence, providing sustainability to her teammates with BLESSING and BARRIER, along with being good backup incase your main fighters are defeated. I can recommend her if you're looking for a good support variant, though if not she can probably be saved for another point in time.
° She can really get going once you gain her Ping Check Marquee, as it'll pair with her secondary abillity to make her very oppressive on offence, along with giving her more frequent damage output in general.
Timeless I'm honestly unsure of since I haven't invested in her, but I hear she can be a great damage dealer provided you can avoid being hit, especially with her ENRAGES and infinite STAR power. You'll probably need someone else's opinion on her though, so sorry about that . _.
