Upload & Sell: Off
Most of the links go to slide films, and not print films, or negative.
If you want natural contrast, Fuji Reala is hard to beat. A very fine grained film which is suitable if you have good lenses. It is 100 ISO only.
Most consumer grade films have higher contrast to compensate for crappy amateur lenses and dull weather. In harsh light the contrast with them good lenses might go over the top.
Kodak has (still available?) some fine emulsions, like Portra VC (vivid contrast) and NC (Natural Contrast), available in 160 and 400 speed. They are different and most people I am sure would prefer the VC over the NC. I would too, unless light is harsh.
It's been a while since I shot film other than the three above, but I prefer Fujicolor consumer grade negative films to the Kodak counterparts as a whole. The high speed Kodak ones are crap to print, I should know. I've printed thousands of them over the years and the emulsions got significantly worse over time. They seemed to sacrifice color fidelity to gain some latitude on the Kodak Gold high speed emulsions. They got harder to print and never looked as good as other emulsions.
None of the negative film emulsions are happy being underexposed and if you are ever unsure you should expose more. (Open up/longer exposure time.)
Developing is key and a crappy lab might even screw up the basic development of the film, so don't hand in all rolls at once if they are important to you. As a side note I should say don't hand in films after a long weekend. Most labs don't top up before the long weekends and don't rinse the machines well enough so crystals form and developing can be spotty in the first few days after a stand still. I have seen it over and over again.
If we had to shut down for a few days we topped up for evaporation loss and rinsed a lot. After a stand still we had to replenish and if we had some past best before date film we would chuck in 8-10 rolls of unexposed film to stir it up and pop the lid and rinse the film trenches. Chemical build up/residue on the squeegee rollers are one of the culprits of scratched films. They should be cleaned regularly and changed periodically.
This was common knowledge for the old timers but I think most that are working in labs nowadays don't even know what is happening inside the machines, how to go that extra mile and most have probably not even flipped through the manual. They just do as they are told.
If films come out scratched it is "never" their fault.
Do I sound harsh? Maybe, but it is also a matter-of-factly opinion based on discussions with people running photo labs both now and then. I have visited pro labs in most parts of the world that have a pro attitude and a very amateurish handling of negative film, machinery and chemicals. At one "pro" place in the US I watched a short guy walk past in the background with my 36 exp rolls in a tangle - dragging the ends on the ground going to the sleeving machine. He didn't have the brains to raise his arms above his head. When I pointed it out to the clerk the clerk said "I don't think the did that" and when I asked how he could say so if he was standing with the back to the guy he didn't know what to say. When examining the negatives the ends were dirty and scratched. I got a 10% discount. Wow.
So, find a clean lab and make sure the staff are tall, dedicated and professional.