The word is sandwiches. Singular, sandwich. Named for the Earl of Sandwich. Or the Islands now called Hawaii. Either way, that's how it's spelled.
The and, even if not spoken, is implied.
The verb must agree with the closest member of the subject list. "There was beer, chips and sandwiches." If this disturbs purists, then the sentence must be recast: "There were sandwiches, chips and beer."
And all rules are made to be broken. Give me an hour and I'll find an idiom that breaks this rule. Or someone else will...