Rikku's MixOverdrive in Final Fantasy X allows her to combine any two items to create a multitude of effects. Every stockable item in the game can be mixed, and there are quite a few combinations that can be used to get the same result. Once a new mix has been achieved, it will be added to the list in Rikku's Overdrive page in the menu, however the various combinations for the mix will not be shown.
Abilities are capped at 9,999 HP and 999 MP damage or recovery unless stated otherwise, even if Rikku has equipped a weapon with the Break Damage LimitAuto Ability.
Recovery
Mix
Effect
Ultra Potion
Full HP recovery for all party members
Panacea
Cures abnormal status effects for all party members
Ultra Cure
Cures abnormal status effects and gives 50% HP recovery for all party members
Mega Phoenix
Revives all KO'd party members with full HP
Final Phoenix
Restores full HP and revives all KO'd party members with full HP
Elixir
Full HP and MP recovery for one party member
Megalixir
Full HP and MP recovery for all party members
Super Elixir
Cures abnormal status effects and gives full HP and MP recovery for all party members
Final Elixir
Cures abnormal status effects, gives full HP and MP recovery, and revives all KO'd party members with full HP
Enhancement
Mix
Effect
NulAll
Casts all four Nul-Spells on one party member
Mega NulAll
Casts all four Nul-Spells on all party members
Hyper NulAll
Casts all four Nul-Spells, plus Cheer and Focus on all party members
Ultra NulAll
Casts all four Nul-Spells and grants all stat boosts on all party members
Vitality
Doubles max HP of one party member
Mega Vitality
Doubles max HP of all party members
Hyper Vitality
Doubles max HP and casts Cheer on all party members
Mana
Doubles max MP of one party member
Mega Mana
Doubles max MP of all party members
Hyper Mana
Doubles max MP and casts Focus on all party members
Mighty Wall
Casts Shell and Protect on all party members
Mighty G
Casts Shell, Protect, and Haste on all party members
Super Mighty G
Casts Shell, Protect, Haste, and Regen on all party members
Hyper Mighty G
Casts Shell, Protect, Haste, Regen, and Auto-Life on all party members
Freedom
No MP Cost for one party member
Freedom X
No MP Cost for all party members
Hero Drink
High critical hit rate for one party member
Miracle Drink
High critical hit rate for all party members
Quartet of 9
All abilities inflict a minimum of 9999 damage or restoration with each hit for one party member
Trio of 9999
All abilities inflict a minimum of 9999 damage or restoration with each hit for all party members
Hot Spurs
1.5 times Overdrive for all party members
Eccentrick
Double Overdrive for all party members
Non-Elemental
Mix
Effect
Grenade
Deals small amounts of damage to all enemies
Frag Grenade
Deals small amounts of damage and inflicts Armor Break to all enemies
Blaster Mine
Deals small amounts of damage plus Darkness, Silence and Sleep for three rounds on all enemies
Hazardous Shell
Deals medium amounts of damage plus Poison, Darkness, Silence and Sleep for four rounds on all enemies
Pineapple
Deals medium amounts of damage to all enemies
Calamity Bomb
Deals medium amounts of damage plus Poison, Darkness, Silence and Sleep for five rounds on all enemies
Cluster Bomb
Deals large amounts of damage to all enemies
Potato Masher
Deals large amounts of damage to all enemies
Tallboy
Deals large amounts of damage to all enemies
Chaos Grenade
Deals large amounts of damage plus Full Break, Slow, Poison, Darkness, Silence and Sleep for eight rounds on all enemies
Nega Burst
Reduces enemies' HP by three-quarters of their current HP
Black Hole
Reduces enemies' HP by fifteen-sixteenths of their current HP
Sunburst
Deals exactly 19,998 damage to all enemies
Elemental
Fire
Mix
Effect
Heat Blaster
Deals small amounts of damage in five bursts to all enemies
Firestorm
Deals medium amounts of damage in six bursts to all enemies
Burning Soul
Deals large amounts of damage in nine bursts to all enemies
Brimstone
Deals medium amounts of damage in three bursts plus Poison, Darkness, Silence and Sleep for three rounds on all enemies
Abaddon Flame
Deals large amounts of damage in three bursts plus Poison, Darkness, Silence and Sleep for three rounds on all enemies
Lightning
Mix
Effect
Thunderbolt
Deals small amounts of damage in five bursts to all enemies
Rolling Thunder
Deals medium amounts of damage in six bursts to all enemies
Lightning Bolt
Deals large amounts of damage in nine bursts to all enemies
Electroshock
Deals medium amounts of damage in three bursts plus Poison, Darkness, Silence and Sleep for three rounds on all enemies
Thunderblast
Deals large amounts of damage in three bursts plus Poison, Darkness, Silence and Sleep for three rounds on all enemies
Water
Mix
Effect
Waterfall
Deals small amounts of damage in five bursts to all enemies
Flash Flood
Deals medium amounts of damage in six bursts to all enemies
Tidal Wave
Deals large amounts of damage in nine bursts to all enemies
Aqua Toxin
Deals medium amounts of damage in three bursts plus Poison, Darkness, Silence and Sleep for three rounds on all enemies
Dark Rain
Deals large amounts of damage in three bursts plus Poison, Darkness, Silence and Sleep for three rounds on all enemies
Ice
Mix
Effect
Snow Flurry
Deals small amounts of damage in five bursts to all enemies
Icefall
Deals medium amounts of damage in six bursts to all enemies
Winter Storm
Deals large amounts of damage in nine bursts to all enemies
Black Ice
Deals medium amounts of damage in three bursts plus Poison, Darkness, Silence and Sleep for three rounds on all enemies
Krysta
Deals large amounts of damage in three bursts plus Poison, Darkness, Silence and Sleep for three rounds on all enemies