Floating platforms are often a staple in platforming games, the HTFA series being one of them. These platforms can be seen suspended mid-air and some even move in a fixed pattern.
Petunia standing on a static floating platform in HTFA 3.
A cloud as a moving floating platform in HTFA 3.
Cuddles riding a variant of floating platform (HTFA 6), which is basically a platform attached to a railing. The railing itself can be found either attached to the wall or nothing (thus floating).