I would nominate the following three culprits: slugs, earwigs, and sowbugs/pillbugs. Don't let anyone tell you that the last two don't cause damage to plants because they DO! ;-)

You're going to have to do some trapping to see who's been doing the damage. Sowbugs/pillbugs and earwigs can be trapped with newspaper. For each 'trap', take two or three sheets of newspaper and fold them in half and then in half again, and dampen. You can also take a whole section and roll it up. Place these near or even under the plants that are being eaten and leave them overnight. Be sure to check on them in the morning before it warms up.

To check for slugs, just use that old trick....beer and a shallow dish. Bury the dish slightly in the soil so that slugs can crawl into it to get some of that nice beer.

"Bury the dish slightly in the soil so that slugs can crawl into it to get some of that nice beer. "

LOL...thanks for the tips rhizo!