>>14259344
Suikoden, by virtue of only having 30 odd spells, 4-12 available to a character at any time depending on the character, with some of them locked spells, or just 4 per character in 1, which you should ignore for the purposes of this explanation, since Suikoden 1 was very very basic.
Fire, Water, Wind, Earth and Thunder. Each set focuses on general roles. Fire and Thunder are damage magic, Earth is support, Water is healing, and Wind is a hybrid of all of them with useful instadeath moves.
There's also, depending on the game, tertiary elements like Darkness (health absorption), Punishment (high damage and insta death but damages you), Pale/Blue Gate (Varied elements and fuckhuge damage with minor effects but can only be used by mage characters), Resurrection (Damage that does huge damage against certain enemies w/ easy healing and revival) and so on and so forth. The unique rune your character gets each game is always geared to get spells based on what would be useful at that stage in the game.
However, the game balances this out by making magic points scarce with it being anywhere from very rare to impossible to have a consumable item restore them, and when they do they tend to slap on bad status effects.
the Suikoden series has been buggy so there were exploits that weren't intended which we're going to ignore, and all the spells are designed to be overpowered since they're limited use, so if you want to make every spell useful you have two options.
1. make one spell per function, which can make your game very bare depending on your complexity
or
2. Limit your spellcasting and cut your player off from restoration of spellcasting strictly, so that earlier spells get use because it's all they have left.
Note that this only counts for pen and paper/RPG type situations, in an action game you should treat spells as functions and have upgrades replace the earlier spell as if it didn't exist, or just not change its name.
After a certain spell count, there will be useless or redundant spells. So the idea to make useful spells is to design your game around your spells/skills FIRST, and to not fuck up when you code, because THAT is when spells get useless the most.