A modifier plus 거 names things by a quality rather than by noun, and 많다 says there are plenty. 예쁜 거 많네 (there's loads of pretty stuff here) is what you say on walking into a shop, and it turns up four times in these lines. The same frame handles 궁금한 거 많아 (I have lots I'm curious about) and 유통기한 지난 거 많을 것 같아 (there's probably a lot past its expiry date).