This sound effect can be found on Cartoon Trax Volume 1, which was made by The Hollywood Edge. It's a higher-quality version of Sound Ideas, ZIP, CARTOON - COWBELL RATTLE AND ZIP from the Hanna-Barbera Sound Effects Library, but with a "thump" at the end.
Sound Effect Description
Rapid Cowbell Shakes - Hollow, Metallic Footsteps, then Slip & Land with Thump.
Clean, Full Length and Unedited Link to the Sound Effect