Dinner and drinks in Center City:
Charlie was a Sinner (vegan)
Bar Bombon (vegan; same owner as CwaS and HipCity)
V Street (vegan)
Vedge (vegan; same owners of VS)
Su Xing (veg*n; typical Chinese fare; been awhile since I've been there but pretty sure they don't have a bar)
Casual / To-go:
P S & Co (veg*n)
Snap Kitchen (veg*n; multiple locations in center city)
Not quite center city but worth swinging by if you're close: The Tasty (vegan), Blackbird (vegan), Grindcore House (vegan, cafe), Dottie's Donuts (vegan). Philly has a ton of veg*n options, so these are just a few. If you're looking for a specific cuisine I can throw out other suggestions.