To find the surface effects go to any weapon holdable bp, these can be found in the holdable items folder inside the items folder. Then go to the class defaults and search for Surface, there you will see all the setting for the surface particles, sounds and decals. You can then set which effect you want for each physics surface type.
Below is a quick guide on how to add new surface types, also linked below is Epics documentation on Phyics materials if you want to know more on this.
First go to you project settings, then to the physics category. The scroll down to the physics surface list, here you can add new surface types for materials like wood metal stone etc. Start by changing the first None surface type to the name of your surface for this guide we will use wood. So it should look like the image below.
Now click the save all button in the content browser and restart your project.
Next go to materials folder then to the PhysicsMaterial folder right click in an empty space in the content browser and go to the physics category and select the Physics Material, then select the physics material option in the window that opens and press the select button.
Then you can rename this materiel to what ever you want but I will call mine PM_Wood. Now open the materiel.
Then in in the physical Properties category there is a drop down option you can select you new wood surface type. (If its not there you may need to restart the engine for it to show up).
Next you can go to any wood materials open them and in the details panel there is an option called Phys Material, there you can set your PM_Wood. This apply the physics material to any place this is used.
Next just go to the weapon holdable blueprint that you want to set the effect for like the BP_Axe for example and in the Class Defaults search for Surface, there you will find the settings for decal, sound and particle effects that you can set for your new surface type like the video below shows. Make sure you set the Decal Size for your surface type as well.