Big pictures that are aesthetically pleasing, preferably of just one girl. It'd be nice if it had an open background and good exposition. A good example of what I mean by that is a picture similar to these:

post #1785144 (but without text)
post #1540715
post #1472345
post #794881

Nothing too detailed or crowded...
Simpler = Better

Any suggestions are appreciated <3

Searching aspect ratio tags (eg. 4:3 and 16:9) or height/width metatags ("width:x height:y", replace x and y with numbers) will help you find suitably-sized images.

Every image in the Clean Beauty pools I made some time ago contain a single character. You may find something there.

Links to pools (Female, Intersex, Male):
rule34.xxx/index.php?page=pool&s=show&id=239
rule34.xxx/index.php?page=pool&s=show&id=240
rule34.xxx/index.php?page=pool&s=show&id=241

A handpicked example from the CB Female pool:
post #1070730

Some other tags, like "plain_background" may help as well.

The "wallpaper" tag is probably a good place to start too.
post #14050
post #28636
post #93458

I used this... rule34.xxx/index.php?page=post&s=view&id=1587005

It's not porn, but a good wallpaper or lockscreen image is a picture you take yourself of your vacation or a gorgeous sunset. Relaxing! :3

what are good ahegao wallpapers? pm me with suggestions

if you want wallpapers go to konachan.com