Curaga is a magic spell in Final Fantasy VII Rebirth. It is provided by
Healing Materia, and is the highest-tier curative spell above 
Cure and 
Cura. It provides a very strong heal, but has a moderate MP cost of 12 and a prohibitive cast time.
Use[]
Curaga can be cast by a fully leveled healing materia. The spell provides a great heal that can likely fully heal a party member, even when cast by party members with lower 
Magic. However, its biggest drawback is that it has a lengthy cast time, which can leave the caster vulnerable while using it. If not used carefully, the caster can be interrupted or killed before getting the spell off.
Curaga's strength as a heal makes it an invaluable spell, especially at greater levels when MP pools increase. It is the most ATB-efficient way to cure a party member. However, its cast time can be an enormous drawback.
Using 
Magnify Materia can allow the caster, especially one with a high Magic, to more than likely heal the entire party at once when casting the spell. This makes it invaluable to have this pairing on at least one party member in most circumstances, especially given that the alternative, Pray, has a smaller heal and costs two ATB charges (but no MP).
The Swiftcast Materia becomes essential when using the materia in solo gauntlets, and very important in other contexts. This alleviates (and at later levels of the materia, eliminates) the long cast time and makes Curaga safe to use, making MP the only limit to the spell.
Both can be used at once, but this will require four ATB slots as it requires two healing materia equipped on one party member, which is an inefficient use of slots. At earlier levels, Magic Efficiency Materia can be useful also to alleviate the hefty MP cost of the spell. Magic Focus Materia is more than likely redundant due to the spell's potency on its own.