I don’t know if someone else posted this before, but this feature is something I’ve (and I know a lot of other people too) been searching in Renoise for years and made me take the decision to change to other daws. Yesterday I found an easy solution:
It’s pretty straightforward. Just set your sample directory on preferences and let it scan. Automatically it will detect the bpm and somehow tag them (you can change this). You can make it sync to Renoise and play it at the note you want without loosing sync with the Renoise bpms.
It can also help you organizing your sample library and drag the samples to Renoise (it works as if you drag a wav from finder/explorer to Renoise)