Here are some options for hardware shopping. Most of these you can order through the online method. Sometimes though it is just fun to go to the stores in person to figure out what hardware you should get. I can spend a couple hours staring at hardware, trying to decide what to get! Sometimes the hardware I find gives me the inspiration for how I am going to create a piece of furniture. I love these amber gold pulls. Very clean lines and simple (click my affiliate link to see).
Lee Valley (a Canadian company that has a great online catalog and so many option for hardware, including reproduction vintage, also ships)
Forge Hardware Company (they have great contemporary pieces) you can look at all their product on their Instagram page & Etsy
D Lawless Hardware (check their clearance section)
Lowes (way more options if you look at their online selection)
Pier 1 Imports
TJ Maxx, Marshalls
I'll update this as I find more places.