Infinite Jump:

Spam jump under a low ceiling, click the "I'm Stuck" button, or move into an area with an open ceiling. This will cause you to jump into the air. The height of your jump depends on how many times you click the space bar while under the structure.

Entity surfing:

Stand on top of an entity (Trash Can, Trash Bag, Box, Wheelchair, Basketball, etc), then jump and pick up the item in rapid succession, causing you to jump into the air.

Carhood Glitch:

Stand, then crouch on a moving car to launch it into the air.

NPC Relocation:

Kill a vendor NPC. The NPC will respawn and stay wherever you move their body.

Basketball flying:

Pick up basketball, look all the way down until the basketball starts to glitch, then hold the walk backwards key.

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Let me know about any other glitches you find, and I'll add to this forum and make a video displaying it.