Many of these sample packs were created by ripping old spoken word cassette / VHS tapes found at thrift stores and such. I do not own the copyright to this material.
I try to only grab obscure / old material that I think nobody would ever care about, but who knows. I also will never charge $$ for these sorts of samples.
So with that being said... be careful if you are using this in released work. I unofficially suggest that you Re-pitch / chop / obscure the samples in some way, then don't worry about it. But officially: don't use these in released work, they are for "educational purposes only", and talk to your lawyer, etc, etc.
I recently got into some collage art and have been buying grab bags from record stores for album covers to x-acto elements out of. Figured I might as well scroll though the records themselves before tossing them, and actually ended up finding some fun stuff. These packs are some collections of samples / rips from those rando records, roughly grouped by category. They are relatively unprocessed, other than being normalized, but they sound nice and could be some nice fodder for your sampler. This article by an internet stranger aligns with how I feel about using unlicensed samples.