upon banerjee's suggestion I am using MGMAT SC
book along with OG and I would recommend it as well
I'd second using MGMAT's materials. Having taken the entire online course, I have all of their guides.
What I like the most is they've organized each SC topic, S-V agreement or Idioms, and list all the OG questions that test on that. So you can focus on your weak areas instead of taking a bank of 25 SC questions and only getting 1-2 questions to help you improve what's needed.