Honda has about the quietest one. Still too loud in a campground where I believe they should be banned.

You do pay more for the quieter ones. two strokes are really loud so go for a 4 stroke engine. I built a wooden box lined with styrofoam to keep the noise down. At first I built a plywood box with no bottom on it to put over the smaller generater, thinking it would quite it down a lot. Not so! The solid plywood box acted like a speaker and actually increased the noise. I added the styrofoam and now you can hardly hear it.