I have a few.
There was a device called a "steam and mash" that I only saw at closeout places. I bought one and one gifted to me.
Essentially you quartered potatoes and other things like squash, it did everything else including mixing up the results.
Seriously - when I was taking care of my father I would take a 10 minute break, run to his house and drop in the potatoes, go back to work and have mashed potatoes ready for him when I got off of work an hour+ later.
The other was the pre-cursor to the George Foreman grill. The salton (the same people that produced the foreman grill) toastmaster grill. I really just use it to put grill marks on meat. I cook the meat using other methods and just put on the grill marks with these (yes, I have multiple - I get every single one I see at thrift stores).
The origional home vacuum tumbler. A manual unit made by a retired butcher in Minn. manual pump, etc. I bought one and loved the results, I actually took a vacation day to go to every Mills Fleet Farm within driving distance to get every one when they were closed out for $25. My xmas gifts for the year. I actually upgraded to a unit large enough to do a whole turkey - again, closed out at Drugstore.com for $50 and the turkey attachmernt (listed for $150, was $25 at Cabella's bargain cave. Some spice manufacturer in Wisconsin was trying to sell that system for $500.
Laugh if you want - the smaller ronco rotisserie. $25 for refurb units at Amazon - I bought a dozen to give as xmas gifts, and it was great for my father. Again, taking a quick break from work and putting in a chicken or duck and having it done when I got out of work and acceptable to his specificatons (My mother was a friend of Julia Child and I was held to her standards when I had time to cook).
Being able to do things Dad liked with little or no time was a blessing
Hamilton Beach flat bread grill. when I have the scouts over, this is a simple thing to just put outside with a rice maker.
They can take care of themselves without my worrying about a grill, etc. One of those things I don;t care if it gets dewtroyed as well. I *THINNK* It was $25
what I would never buy again - there was a bagel maker that included cooking in a wet wash. something sheap or I would not have bought it. Used it once and it is in the garage to be donated the next truck load I bring to Salvation Army/St. Vinnies.