RoleMaster.
spells of like kind are organized in lists. as you gain "XP" you can spend them on the next level of a particular list. each level is more powerful than the last. i think, but am not positive, that all lists had 10 spells. here's a fake example:
Cold Law
1. Ice Touch - 1d4, touch
2. Resist Cold - immune to 10 pts of cold damage
3. Ball of Frost - 3d6, ranged area effect
4. Ice Touch II - 5d4, touch
5. Resist Cold II - immune to 15 points of cold damage
6. Ice Wall
7. Ball of Frost II - 8d6, ranged area effect
8. Resist Cold II - immune to 30 points of cold damage
9. Frost Storm - 12d6, ranged area effect
10. Summon Ice Beast
depending on class, background, etc. you have different access to lists.