I currently use five different adhesives on the layout. My most used is Elmers White. I just went through a gallon jug of the stuff, as it's super useful for thinning down and using for ballast, and scenery, and wood based materials.
I use thin and thick CA when the thin won't make the contact, and when I'm putting two different materials together (like the flatcar thread).
Then I use Gorilla glue for when I really have to hold something down. I used some the other day on a base for a station that was warped. I glued it directly to the layout.
Then I use another all purpose glue for holding weights, and having a stronger hold on keeping odd materials (other than plastic) together.
Oh, yeah, then the ever present plastic cement in the tubes.
I've used latex caulk/ liquid nails- projects, for holding down the foam sheets that are part of the base of the layout.
Now if you REALLY want to drive my wife crazy, then we can talk about the stuff I squirrel away and scrounge!
(she tosses stuff if she doesn't think SHE needs it!
) The other day we went down to the local reservoir trail, and they have this really great HO scale Bluestone. She saw the bag of stone, and just scratched her head!!
Tools? Well, anything from a framing hammer to a jeweler's screwdriver has been used here. Pics for that later...