I slide over snow but I have no wheels. You can sit on me and ride down a hill. What am I?

I’m a soft little sheet on a kitchen roll, I chase after puddles and crumbs on patrol. I’m made to help, then disappear, A tiny hero we keep near. What am I?

High above the ground I stay, Keeping floods from walls at bay. When I'm clogged, trouble's near, Though few notice me all year. What am I?

A simple switch is all I need, To help you work or help you read, I stand beside you through the night, With just one touch, I bring you light, I shine above, but I'm not the sun, Until the daylight has begun, Sometimes I'm tall, sometimes I'm small, Yet I can brighten one and all.

It isn't a fable, mercuries neighbor makes life able, But I am next to him on a different table.