Services like Splice or Arcade offer vocal cues via subscription. While not strictly "free," they offer free trials. If you download a cue during a trial and use it in a track that blows up, you are usually fine. However, if you monetize a video using a "Free" pack from a random forum, you risk demonetization.
Start with Bandlab or Cymatics. Download one pack. Do not go on a hoarding spree (you will never use 4,000 vocal samples). Pick 20 that fit your vibe—deep voices for techno, energetic shouts for house, whisper-soft hooks for lo-fi. Vocal Cue Pack Free Download
The long answer is that a is an incredible starting point, but it is your processing and context that turn a generic "Yeah" into a floor-filling anthem. Services like Splice or Arcade offer vocal cues