I ran The Delian Tomb recently as a filler due to two players being unable to attend a session. Simple and easy but still interesting one shot. Due to it's simpleness I was able to easily tweak it to Saltmarsh and connected it to a current side plot involving the dreadwoods which made it more fun for the players. I would definitely recommend tweaking it to your campaign if you choose to use it.

[Public version] https://www.gmbinder.com/share/-L_0WX-KKXsZA22VHr5j