Thats a pretty thorough effort from ShadowWarrior. One he missed from my list that is worth its weight is one by sound toys that is called echoboy or similar. Its got verb and delay all in one and thats really nice echo plug.
Most commonly i use delay for thickeninning or doin the fake Haas effect.
vesko effect make a nice little freeware one and i use this a lot. Just for one ping in the opposite speaker, then filter it a bit to model the reflective surface.
i have used this so many time as its ease of setup is quick. There isnt a mix that doesnt use the Haas effect or some form of doubling somewhere.