Derrk Uses particle systems to grow grass on any object. Has some links to free grass objects, and car. (Geometry nodes also allows this and Uses nodes to place objects.)
Polyfjord has a great tutorial on making a fireball. He first shows us how to setup the fireball object, then he does the shading for the falloff and intensity of the fireball, (He uses some math nodes to do this. Don't be scared of math.) His format is to show some cool effect of the particle system, and then explain the settings he used to make them. And has an advanced section (I wish more people did this) where he has some tips like when he uses some modifiers to make the ball change shape as it moves. (so smart) I kept on wondering, could make a rocket exhaust with this tutorial? (next project) He even shows you how to add glow using the compositor. (Tip, he renders out the whole simulation, so you can have real time updates in the compositor) Then at the end of the video he has a great suggestion of what to do with your new found fire and smoke simulation powers. Just awesome.