If you are looking for the modern evolution of Soundplant, is currently the strongest contender.
The "gold standard" for live electronic performance. You can easily map every key on your QWERTY keyboard to a specific sample or loop within its or session view. Best for: Complex live shows and music production. soundplant alternative
While technically a full Digital Audio Workstation (DAW), is widely used as a high-end soundboard. If you are looking for the modern evolution
If you're looking for an alternative to (the keyboard soundboard software for macOS/Windows), here are some solid options depending on your needs (live performance, gaming, podcasting, or just playing sound effects via keyboard): soundplant alternative
(if you want a tracker + soundboard) or Bitwig/MPC Beats for pad-based triggering