Driver's side clunk, driving forward after starting truck

Well I think we're talking 2 things here. The ABS is like @Sc00ter said, a bathtub fart. However what I think the OP said, a slap/clunk, going forward. What you didn't mention, do you back into a parking spot? And then pull forward. This happened in my '09 taco and drove me nuts and now happens in the '19 Tundra. I think the caliper or pads or who knows what, moves slightly from forward to reverse or reverse to forward. It's a more metallic slap than the ABS.

 

I back into my driveway. Hope I don't start noticing it now that you told us about it.