Same here. There's a Novel Idea on Passyunk Avenue but that's in South Philly. The Book Trader is by Independence Mall and has a really good selection. Mostly Books is another good one near Queen's Village.

Headhouse Books at 2nd and Bainbridge.

Book Trader, Book Corner and Philly Aids Thrift are my personal favorites.

Love Book Trader

Bookhaven.

Book Haven on Fairmount and 22nd is a great classic chaotic good book store

Fox was unique

Brickbat

Book Trader, Headhouse Books

If lightly used is ok. Mollys in Italian market.