Let me get my stethoscope and check. lubDUB lubDUB lubDUB for a normal heartbeat, although I've never actually had to use that, conveying the human pulse with an EKG line instead.
Given that I write military history, and particularly a lot about aviation, there's a lot of BOOM, krkBOOM,, and such for explosions, wooOOoowooOOoowooOOoo for sirens, veeeeROOOOOOOMMMMMM for fast flying aircraft, thwupthwupthwupthwup for helicopters and also for rounds hitting dirt, and for various weaponry, BOOM! POW! kaBLAM, BRRRATATATAT, PRRAKATAKATAKA, and especially in Tiger on the Storm, the A-10's notorious BRRRRT!