Just BE CREATIVE. Put the "experimental" part in experimental beat music.
Record stuff yourself. Be it on your laptop's mic, cellphone, camera, cheap dictaphone, whatever. Go around, find or make some interesting clatter, and layer that stuff. I do not understand this idea that percussion sounds can only come from a drum machine or a record or a sample pack. The cheapest of sound recorders can capture raw sounds fantastically. Just do some processing like EQ and compression, maybe some saturation, and you're good to go. Sooo much more gratifying, and really not difficult by any means.
This world where all sounds come from sample packs blows me away. Just about everyone with a computer and a recording program has more than enough tools to put together some wild and unique sounds, yet people want others to just make those sounds for them. I hope people are at least manipulating these sample packs.
I once made some location based beats where I went to a particular place, say a busy cross street, recorded about a minute's worth of audio on a shitty digital camera (just ripped the audio from the video), and then took sounds from that recording to create a drum kit. If there was a low boom, there's my kick. If there's a higher crack, there's my snare. Something even more high pitched, there's a hi hat. And so on. Feel free to even pitch stuff up and down. Do whatever you want, just keep experimenting.
Take this approach a step further by maybe layering that lower boom with a sub sound, or layer your snare-ish sound with an actual clap, whatever, and there you have some unique sounds to be proud of. Really not hard to do. Maybe it'll turn out you have sounds interesting enough for others to want to rip them for a sample pack.