Clarendon is a serif font. It goes well with Theinhardt, Minion, Sentinel, Futura, Sean, Helvetica Neue and League Gothic. If you're thinking about using Clarendon then try 72px for headers. Give 30px a shot for content.
People commonly tag it as agency, portfolio, design, case study, contact, form, coffee, shop, ux and clarendon. You can get it from Fonts.com, Fontshop, Fontspring, MyFonts, Typekit and YouWorkForThem.