So I'm familiar with DOS: EE and the element mechanics of combat, but I'm not sure if that applies to DnD 5e.

But last night I threw a fireball cantrip at a group of goblins standing in grease, and what do you know but the whole gang go up in flames!

Does anyone know of other great spell or skill combinations you can use, especially to deal with groups?

Also what are your go-to combat setups?

I'm currently running a Druid, Cleric, Warlock, Fighter so if you can think of combinations from those classes that would be great too.