I dented my wheel bad driving over a pothole. I'm planning on buying a set of new wheels and tires entirely.
Im sorry I tried to research through the threads but I guess Im not understanding the sizing too well.

I am looking for: 19' wheels but I would like the wheel to sit flush with the fender.
What are the dimensions of wheels I need to shop for?

I am driving an 2014 IS250 F Sport staggered.
I've seen set ups with spacers installed but if that can be avoided, that'd be great.

 

Welcome Wasa!
If you're looking for 19" staggered, then the most common sizing would be Front: 19X8.5 +35 offset, and Rear: 19X9.5 +40 Offset.
Depending on the wheel you buy, the manufacturer may offer those exact offsets or something very close.
You could as low as +32 on the front and +38 on the rear...for a comfortable fitment with no rubbing.
Any further and then it starts to be come hit or miss...depending if your vehicle is lowered or not.