Many people bet their work on Kontakt https://www.native-instruments.com/en/products/komplete/samplers/kontakt-5/ but really is about the third party content that might make it the best sampler... The included sounds are good of course, but I think the wide variety of extra libraries makes it appealing to so many. And rightfully so.

There are many other options, but mainly it's about a "host" that will play some libraries of some kind. And these host can be Kontakt, UVI Workstation, SampleTank, Air Structure, Presence XT, to name only very few. This if we're talking sampled sounds.

On the other hand, look up for freebies, you might be surprised what you can find. There is a ton of them, some better than others. For instance http://www.vst4free.com/index.php?plug-ins=Organs&l=0

All in all, there are possibilities out there, but you just need to spend some time exploring. We're really living in a time of diversity!