Final Fantasy VII/Materia

Strategy and challenges
Mastering every materia in Final Fantasy 7 takes an extremely long time. Still, mastering all the materia of the same color allows to get the extremely rare and valuable Master Materias.

Therefore, a player might choose to focus on one or two materia colors, and play through the game three times to get one Master Materia each time. Here is an example of a strategy:
 * Game 1: Green Materia: use the 21 Green Materia, plus the blue All materia and the yellow W-Magic materia, that can be used only associated with Green Materias; 24 different materias. After Aeris, the characters with the best magic attributes are Cait Sith and Vincent.
 * Game 2: Red and Blue Materia: use the 16 Red Materia and 11 Blue Materias (excluding the two that are incompatible with the Red), plus the yellow W-Summon materia; most of the Red Materias simply damage the enemies, therefore the Blue ones will give some variety to the game; 28 different materias. Red materias require the most AP to master; Cid has the best materia-growing weapon in the game, and Yuffie has some very good ones, too.
 * Game 3: Yellow and Purple Materia: use 11 Yellow Materias (excluding the aforementioned W-Magic and W-Summon), the 17 Purple Materias and the blue Counter materia, that can be used only associated with Yellow Materias; 29 different materias. Barret, Tifa and Nanaki have very high physical attributes and will get the best from the yellow materias.

Note that the purple Chocobo Lure materia is necessary to get past one step of the game and to obtain some rare materias; also, the purple Enemy Lure materia allows to speed up the growth of the materias.