List of different track options?

RCS - http://rossswitches.com/

GarGraves - https://www.gargraves.com/

Atlas - https://shop.atlasrr.com/c-1017-o-3rl-track.aspx

Menards - https://www.menards.com/main/g...-menards/c-14331.htm

MTH for RealTrax & ScaleTrax - https://mthtrains.com/product-line-pages

Lionel - https://www.lionelstore.com/category/Track-and-Power

Then Google online shops to compare prices. Atlas is popular, but a bit more expensive. GarGraves with Ross switches (arguably the best) is popular because of price and their flex track, though nowhere near as flexible as HO. Menards is popular because of price, though they don’t sell switches.

Thanks Dave. I guess I should've probably clarified that I'm primarily looking for Lionel at this point, since I'd be setting something up on the floor; when I get my house built, maybe I'll have something proper on several sheets of plywood.

I was wondering what options I have for traditional (stamped tin I think) O (and for curiosity's sake, O27) track. I looked at the Lionel link, for instance, and it only lists Fastrack, which I'm not interested in at this time. If I had a budget for it, I'd totally do the Fastrack route or something similar.

Sorry, other than Menard’s, eBay and Google, I have no idea.

Traditional "stamped tin" track is known as tubular.  AFAIK, Menards is the only company that is currently manufacturing it.  However, O-gauge tubular track is widely available at train meets at reasonable prices.  If you're willing to do some cleanup work, tubular track can be found very inexpensively - since it has fallen out of favor, many folks are desperate to get rid of it.

Various curvatures are available.  Basic O track is nominal 31" radius.  I know that O-42, O-54, and O-72 are available, and possibly others.  Lionel made O-31 and O-72 switches - both are widely available.  I think that K-Line made O-42, but they can be hard to find. 

K-Line also made radius: 31, 42, 54, 72, 96, 120 that I know of.

K-Line track was very well made and more robust than Lionel.  It is a very good value today.  They made 36" and 40"  long straights and they had evenly spaced ties giving a more realistic appearance.  I also have 14" straights.