It's hard to give examples without giving away or naming specific sites, but something like "tough as nails" (already registered by someone in 1999) or "sly as a fox" (registered this year by someone else). Phrases or "pre-formed sentences" such as this are already common in the venacular, so you aren't forcing someone to create new neural pathways to remember them. But could you monentize them?
Opinions please!
Three of them, none of which I promote, have probably next to no activity, if any. And no offers on them either.
The fourth one does get more traffic, but I do promote it a bit, sometimes. It mainly gets used for one special occasion each year. I've never analysed the logs on it, so I don't really know where the traffic gets to it. It serves its purpose, so I haven't worried about it.
By the way,all the above phrases are already taken, most back in 1998 or 1999. Most seem to be domain name only, with no website. I wonder why the owners haven't tried to monetize them, or if they found out it wasn't worth the effort.
You are correct, most of the good common phrases in the English language have already been registered, although I have found a few possibilities left. I still don't know if it worth my while to register them and put up a web site? My guess (and fear)is that if I don't, someone else will stumble across them and do it before me, and end up "making a mint" off them.
Idioms do have some end user demand as they are easy to remember and will cost less to brand than if they made something up. The key is to pick phrases that may have some commercial relevance. The drawback to registering idioms is that you can sit on them for a long time with no sales inquiries and no parking income.
With that being said, I was trying to find an idiom last month for a friend's startup. We ended up using something else, as all the better choices were long gone.