ZapSplat offers thousands of free professional sound effects. They have a dedicated "Office" and "Technology" section which is perfect for explainer videos. They provide high-quality WAV and MP3 files. 4. YouTube Audio Library

Always aim for WAV or AIFF files (24-bit/48kHz) when possible. MP3s are compressed and can lose the "crispness" needed for high-end digital explainers.

Mechanical or digital sliding sounds for panels and sidebars. 3. Character and Organic Effects If your video features characters, you need life-like cues. Footsteps: Subtle thumps to ground the animation.