Všimli jste si stůl, židle a polička s osobní věci

The main verb is "všimli jste si" 2pl. past tense form of všimnout si 'to notice.'

The subject is the implicit "vy."

Všimnout si takes the genitive; stůl, židle and polička should be in the genitive case.

Osobní věci is preceded by the preposition "s" which takes the instrumental case; věc is feminine and declines like kost.