I see there are a few different type of the toe warmers on the market, like the Grabber brand and a few others, any preferences which feel the most comfy and keep the feet warm the longest.

Chet

I have not found any of the heat pad type that work. Seems like they make my feet damp, witch makes it worse. I use heated gear to extend my riding season. Warma nd Safe has some great deals at times, and I plan to get some of their heated socks to try. Aside from that, I have used some booties that go over my riding boots with some degree of success, and Gaters seem to really help more than you would think.

Multiple layers of thin socks work a lot better than one thick sock as well.
Merino wool on the inside if you can find them.

Pete