So there's ReaSamplomatic5000, which has always been a bit of a micky mouse sampler that comes with Reaper. But actually, it has been improved in a recent version! Two things are the ability to import multiple files, and a graphical ASDR. You can drag and drop files for easy loading. You can import a selected item for the arrange window, as well. It won't replace Kontakt by any means, but for quick and dirty sample playback you might get some use outta this. The GUI looks a bit wonky but if you're a Reaper user you should be well used to that.
Some tips for the waveform display, clicking on the upper half will zoom in, clicking on the lower half will zoom out. Mousewheel will zoom as well. You can drag left and right to scroll the waveform. Dragging up and down will resize the waveform.