Somari's emoticons could be:
1. Somari's annoyed expression from his waiting animation
2. Somari's head with an open mouth facing upwards (his unused death from drowning sprite)
3. Somari's lives icon
And custom ones, like Somari's face with various new emotions, and various power-up monitors with custom symbols as the powerups displayed inside.
Grand Dad's emoticons could be:
1. The Fred Flintstone in a star from the title screen
2. The face of the weird Mario from the title screen
And more custom ones, like Grand Dad's in-game sprite facing forward and winking, a confused-looking Grand Dad, and more emotions.
The bootleg Super Mario World Mario's sprites could be:
1. Small Mario's victory pose sprites
2. The unused Lakitu death sprite from that game
3. Wendy Koopa screaming
4. The Fire Flower/Mushroom sprites from that game
And, of course, some custom ones, like different facial expressions for the bootleg Mario.
You could get the sprites from Spriters' Resource, obviously.
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