The closing costs that are mandatory (that you will be charged regardless of which lender you use) are 1) Transfer tax within the County of Philadelphia of 2%--1.5% to the City, .5% to the State; 2) Deed and mortgage recording fees; 3) Title insurance (if you have a mortgage) and title related charged like closing protection letter, endorsements, notary fees, express mail charges, e-doc fees.; 4) escrows (make sure when you're comparing estimates that they're including the same amount of months.)
Lenders usually will give you estimates of taxes and homeowners insurance. Since these are only estimates unless you have a specific property in mind and you've obtained a quote for insurance, make sure not to include these numbers when you're comparing quotes.
The types of fees that will change from lender to lender are basically the rest of the fees. Your real estate agent should be able to review these quote with you line by line if you still have confusion.