There are plenty of choices, but most come down to three categories: Size of image, type of focus and cost.
Image: 6x4.5, 6x6 and 6x9 are the most common. Some have masks that are either built into the camera or that you insert to allow you to shoot two formats, though generally not on the same roll.
Focusing: There are plenty of zone focus cameras out there and just as many with rangefinders. Some are coupled; some are uncoupled. If you're shooting mostly landscapes, zone focus is fine. If you're going to be photographing people and things around the yard and the house, you'll want a camera equipped with a rangefinder.
I just sold two Franka Solida folders. Wasn't going to use them, and I need the shelf space for cameras I use.
Cost: Much is determined by camera maker, lens and features.
Suggestions:
-- Agfa Isolette III with the Solinar lens. Nice camera, uncoupled rangefinders but check the bellows carefully, as Agfa bellows seem prone to pinholes.
-- Zeiss-Ikon Super Ikonta B: Great lens, coupled rangefinder. Will almost always need serviced.
-- Nagel Duo Six-20: Comes with either a sharp Xenar or Tessar lens. You'll need to respool 120 film onto 620 spools.
--Voigtlander Bessa (the real Voigtlander): The Heliar and Skopar lenses are highly regarded. Lens standard susceptible to wear.
--Ikonta 521/16: Look for the Tessar lens. This is an underrated camera. It's zone focus, but it has a very nice lens. Simple to operate. Nearly dumbass-proof.
There definitely are others, such as Balda, Ross and Kodak, though I haven't had any experience with them.
The Zeiss-Ikons seem to be the most popular, because the quality of construction was generally very high.
If possible, try to actually hold the camera. Check for physical damage. Make sure the camera opens and closes smoothly and that the lens bed firmly locks into position. There shouldn't be any play with the lens when it's locked into position.
Check the bellows for pinholes. Look for mold or fungus on the lens. Check the slow speeds on the shutter -- they should whirrr smoothly and not stutter.
See what I mean? Lots to check, and it's why I say, "Expect the worst and hope for the best."