I thought I saw every insane one...
...until I saw this:

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Insane tempo, and a lesser-insanity tempo'd song:

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Lower tempo, but still interesting nonetheless...

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aka. the RICKROLL song.

This next one isn't in Mario Paint, but is great nonetheless.

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Edit: Due to SPAM, Kavinel has been banned.

Edit 2: DUE TO SPAM, Sonic-E HAS BEEN BANNED.