I think I gave a similar answer to somebody who asked the same question. Since you lack an SSR Berserker, either MHX Alter or Hijikata could be good choices. You never mentioned an Extra Class so I suggest Edmond Dantes. As he is, he is good currently but turns into the best AOE farmer with the arrival of Skadi,
Upcoming banners in 2019?
From my roster, you can see that I am totally a F2P player (didn't even roll for the GSSR) and I'm saving quartz to get better servants. I'm wondering what upcoming banners that you can suggest I should roll for this 2019, based on my current Servants. Here's my roster:
Sabers: Musashi, Lancelot, Saber Liz, Siegfried, Nero, Bedivere and Caesar
Archers: Archer Altria, Kuro, Emiya, Robin Hood and Arash
Lancers: Altria Lancer, Tamamo Lancer, Liz, Jalter Lily and Cú
Rider: Martha, Santa Alter, Marie Antoinette and Medusa
Caster: Merlin, Halloween Liz, Caster Gil, Medea, Hans and Mozart
Assassin: Kiritsugu, Kojirou (Currently lvl 92 still waiting for grails to lvl 100), Sanson and Jekyll
I got those SSRs with pure luck ._. Thanks for the suggestions in advance!
Saber : over 9000.
Archer : over 9000.
Lancer : over 9000.
Rider : Ozy, one of the best rider on NA now and he's sitting at Chaldea Boys collection but he share the rate up with Arthur Pendragon ( not Arthuria ), welfare summer servant AOE rider Ishtar.
Caster : cheat level and over 9000, skip unless you want Waver ( Chaldea Boys collection ). Waver also share his rate up with Arthur Pendragon.
Assassin : Assassin Scathach will come again when Summer re-run is back, she is a good AOE Assassin. Kojiro is really good, keep up the good work to raise him.
Berserker : Guda-Guda Meijin Ishin. Welfare AOE Zerker Cha-cha and hard hitting Buster Crit SSR Zerker Hijikata Toshi, SSR Quick Zerker MHXA, summer SR Zerker Nobunaga Oda and also glass Cannon Zerker Penthesilea. I recommended this one because you lack Zerker.
If you need Extra Class, Passionlip and Kiara will serve you well.
On saber your good unless you want an AoE Np
On Archer go get Nobu as a welfare she is very good Archer
Lancer you are good on both the ST and AoE
Caster you've yourself the best one (I wish i have that)
Rider you would probably have both Kintoki and Santer.
On assassins I guess you have already your pick
For Berserker go for Raikou
For Extra there will be AlterEgos coming your way in a month or two