Odds are that someone will have a land, so youll have that as well
Obscura Charm Streets of New Capenna revamped the Esper play style, and as such we transition from controlling cards to cards that can be used in midrange decks, where Obscura Charm can shine
Bristly Bill, Spine Sower Bristly Bill, Spine Sower is continued proof that cards don't need to be wordy and complex to be very powerful
Sadly, control decks are some of the worst decks for flipping battles since they usually don't play many creatures, which means the Serra Angel backside is unlikely to show up very often
If you're sticking to the Vampire Aristocrats theme then the first cards I'd pick up would be Vampiric Tutor (finds Skullclamp and has Vampire in it!), Bloodletter of Aclazotz which doubles your drain / damage output on your turn absolutely wild, Bloodline Keeper provides sac fodder and a strong anthem, Legion's Landing nice thematic ramp, and Sorin, Imperious Bloodlord thematic ramp and removal