made vignetting and iris blur nodegroups for myself to append, as i'm using them over and over again, so i thought why not share them. iris blur is essentially the same as vignetting, but instead of darkening, it blurrs.
I added some "custom values" to the nodegroups to further adjust them in size, feathering and intensity. Feel free to use this however you like.
the two effects are targeted for 1080p and 16:9, but they could be adjusted within the node groups.