I have one head, one foot, and for legs. In other contexts, I can be found be a river or in a garden. What am I?

Treasure is on the tip of my tongue, but if you're like me, you'll never tell

I'll almost always sink in water, no matter how many times I'm skipped I could roll or just sit there, depends on my size and shape I'm almost everywhere in some way If you can't get this you might be between me and a hard place What am I?

I sit on a plate, I’m sweet as can be, blow out my candles and make a big wish, see? But if you hear me talked about when you jiggle and shake, I might mean the part of your rear your momma helped to bake.

I stand on legs but never walk. I hold your thoughts, yet never talk. By day I work, by night I rest, Papers, screens, and hands I host. What am I?