After looking around for a one size fits all hook for my slatwalls, I decided to build one up in F360 to make it scalable and get multiple fits for my needs. I found that my slatwall rows were not consistent even between rows on the same 4x8 sheet. I am using the MDF type slatwall with no reinforcing inserts in the slats.
I have included a parametric F360 file to allow any changes needed to fit your specific slatwall. Use the "Change Parameters" modifier to make most changes, each parameter has descriptions to show which dimension it controls. The slat mount can be altered to get best fitment to your specific slatwall. I found that it was better to have the slat spacing (parameter "flatback_height") just a tad long to allow fitment on more rows.
You can also change the hook size, hook width, extend the hook tip up, slatwall connection width, and much more.
I removed some of the chamfers on the hook arm to help with bed adhesion. The extra chamfers left minimal surface area to secure to the bed.

Sometimes the hook sizing can get wonky going from a smaller hook to a 3" or so hook when using the "hook_diam" Parameter. When this happens, change the hook size back to a 2 inch or so, press enter, and then take it back up to 3" and it should clear out the issues. 3.5 inches is about the largest it will go without giving other errors because the hook base is extending too far beyond the slatwall bracket.

Creality

Ender-3 S1 Pro

No

No

15-20

Print with hook laying on side, no supports needed. If you add additional chamfers to the hook, the tip will want to curl up. I print with 4 top & bottom layers and 3 row walls for strength but its probably not necessary.