The "best" is whatever meets your transportation needs and is light enough to pull.
That it can be pulled without modification (other than lighting and towing equipment) is a bonus. That it can at least be modified for safe towing is a necessity.
Most older GM compact and some GM midsize cars (Saturns are popular) can be towed with automatic transmissions (the lighter duty 4-speed overdrive) as can some imports that borrowed that transmission (like some Honda and Suzuki).
Many front-drive manual transmission cars can be towed without modification, most of these in the U.S. will be subcompacts and compacts. Most front-drive cars can be towed on a dolly, if you can find a dolly that fits.
A few rear-drive manual transmission cars can be towed without modification, most rear-drive trucks can be towed if you disconnect the driveshaft. I know people who do this manually, underneath with the toolbox, every trip. So there is a convenience factor to weigh.
Some AWD and 4x4 vehicles can be towed four down, either because the transmission permits (e.g. Honda CRV, and manual transmission Subaru) or because the transfer case can be put into neutral and the transmission locked up (many, but not all, Jeep models). Not all transfer cases with a neutral permit this, it depends on internal design. Most AWD and 4x4 vehicles cannot be pulled on a dolly, the torque splitters and transfer cases are seldom designed to handle one axle turning and the other not turning.
I have two vehicles set up to tow, a manual transmission regular cab Ranger, and a Honda Fit. If I am going out alone and want to carry bulky toys, firewood, or other equipment, the Ranger is "best" for me. If I expect to be hauling around other people, the Fit is "best" for me.
What is best for me may not be best for you, it depends too much on transportation needs. People will tell you what they tow, and many will tell you that is what is best. Best for them.
Tom Test
Itasca Spirit 29B