Shakespeare was right: there's a summer and winter court. There's also a spring and fall court.
Theology is hard: I'm not sure if the fall court is preservation and the winter court is destruction, or vice-versa. I'm going with the former largely because it's easy to remember. Have a summer-winter axis and a spring-fall axis.
The key feature of faeries is being ironic and tricksy. Summer creates for the purposes of destruction. Winter destroys for the purposes of creation.
The spring and fall courts are nasty.
Think of an old painting. If the painting is in bad shape, barely recognizable as a picture, the fall court will try to preserve it. If it's in good shape, the spring court will try to "restore" it.
The fall court preserves ruins. They preserve wounds and injuries - if you have a gash, the fall court will freeze the flesh. If you have a dislocated joint or broken bone, they will say, "Stop! Nobody move!" If a man is on crutches they will bolt the crutches to his arms so he can't put them away. If you're crazy they will preserve your delusions. If a forest is choking itself they will ensure nothing happens to it.
The spring court restores that which ought to be preserved. If you have a cast on, they will restore you to your cast-free state - before the bone heals. They "restore" your healthy skin with tattoos. If your cancer goes into remission, they will restore it. They will restore life to your canned goods. If a desert forms in a place of peace they will try to invade it. Basically necromantic zombies are pure [spring court].
The summer court creates for the purposes of destruction. They create weapons. They create pathogens and poisons. They create fires and floods. Beings of vengeance generally employ summer court tools. It can be bad as well, but unlike the fall and spring courts they aren't inherently nasty.
The winter court destroys for the purposes of creation. They burn the forest so it can regrow. They drop the bombs the summer court builds. A lot of what they do is destroying fall and spring court fae before they can act up. Certainly my personal favourite; spring fae taste like peppermint. Recommended. The term "god" in modern English is usually misleading; Mars frequently acts as a winter court faerie. No, I'm not claiming they're inherently virtuous.
If you make a deal with fall or spring fae, you will get jacked 100% of the time. The correct answer: just don't. They're pests. These are the ones that deserve the insectoid reputation.
If you want to deal with summer fae, ensure your final end is destruction, or you won't like the results.
If you want to deal with winter fae, ensure your final end is creation, or you won't like the results.