I've seen a few posts on here prior where people had posted about a few of these libraries available super cheap but to get the complete Nine Volt Audio bundle for such a low price is a total bargain.
https://vstbuzz.com/store/96-off-ultima ... orth-2400/
In my opinion these are some of the best REX loops ever created; made with real care and skill. It appears that the secret to creating really versatile REX loops is by making them at a lower BPM than they're ultimately intended to be used at. This means actual slice tails exist and thus the tempo can be scaled up and down more smoothly: