Going to a LGS today to complete my FF deck (beginner)

Going to a LGS today to complete my FF deck (beginner)

I played my first game of commander mtg last night, with a shambled-together deck I made from a bunch of leftover FF bulk and legendaries (my partner bought a ridiculous number of card packs/boosters). I quickly realized I am lacking a lot of cards that would enable me to actually do anything to make my Sephiroth, Planet's Heir work. I have removed any irrelevant cards that won't help me, but have tried to keep as many FF cards as possible. https://www.topdecked.com/decks/sephiroth-planet-s-heir/371b28ae-9851-40bc-96b9-efbe2018a7e1

I'm going to the LGS today to grab some missing cards, about 41 missing cards. I want 10ish more effective dimir towns, 10ish mana ramp cards, 3 or more card draws, and a little under 20 creatures+artifact equipment+etc to support Sephy so he can survive. I want to keep the existing FF cards in my deck so far, and add other cards, but the problem is that I don't know the names of a lot of the dimir cards or names of mana ramp cards. (Other than Sol Ring)

Can anyone provide me with names or suggestions that would help my deck??