you can usually find drum samples on pirate bay, thats where i found all my samples or you could actually use a sampler and sample things but thats a little complicated if you dont know what you're doing but there should be tutorials online
or you could take a standard 808 set and just play around with it and distort it a lot of people take a standard drum and change its sound with distortion, you can make a snare punchier or a kick bassier ect