where I find icons
Not looking for anything this time, but I thought I'd share the places and techniques I use in icon hunting.
wikicon's memories: Good for older sets, but hasn't updated since February 2015 (at time of posting, according to their own post), so if it's a newer role or someone who got famous more recently, I skip this. If you find posts for someone there, it can be worth checking the icon journals, as sometimes the icon maker's posted further sets that haven't yet been archived.
Googling through Insanejournal: Google site:insanejournal.com "icons" "celebrity name", possibly with "canon name" if you're after icons from a particular role (eg. site:insanejournal.com "icons" "demi lovato" "glee"). This can bring up icon journals, pb_updates posts, posts here of other people looking for the same celebrity, and people's memories pages with links to icon posts. It will also, however, bring up communities like pbads where people are wanting to play the face or against the face and just need icons. If you find you're getting a lot of the same journal/comm in your results (lots of pbads posts, an icon journal where the person you're looking for is a tag but they actually only have one post), add -username or -phrase -in -journal -title to your search string to take it out (eg. site:insanejournal.com "icons" "austin butler" -glorafilia).
Googling through Dreamwidth: Again, this is Googling everyone searchable, but here you'll want to search site:dreamwidth.org "icons" "canon name", possibly with "character name" if it's not a main role. The fandom side of Dreamwidth icon making focuses more on canons and characters than the actor, though you may have some luck with musicians.
dwrp_icons's memories: This is the fandom version of pb_updates, with the memories sorted by character. Also try using their tags to find a canon, as icon makers sometimes have more characters in their icon posts than can be added to the memories.
icons and fandom_icons: Both communities have canon tags, though there are a lot of icon makers who crosspost to both.
Tumblr: Google site:tumblr.com/post "icons" "canon name", possibly with "celebrity name" or "character name". Also try Tumblr's search function with search terms along the lines of canon name icons or celebrity name icons. For journal RP make sure you're looking at text posts with 100x100 pixel icons, because you'll often find photoset posts of larger square crops. Along with sizes, you'll also see a couple of different visual styles for icons besides the usual "prettied up crop" you get here and on DW. One has the character cut out and set onto a solid colored (often pastel) background; the other involves wide borders and grids/similar textures over the cap.
Hollow Art:Has a search function for you to plug in your celebrity name. Some of the newer icon makers do the Tumblr thing of borders and overlaid patterns, or make slightly smaller or circular icons.
The Hollowed Artists: The Tumblr that some of Hollow Art's old icon makers moved to while the website kept dying. Their index isn't up to date but they tag well, so put /tagged/celebrity name (or canon or character name) after .tumblr.com in the URL (eg. http://thehollowedartists.tumblr.com/tagged/zelda williams).
Livejournal: Better for older roles, since a lot of fandom's moved to other sites. You can search interests by canon, celebrity name, or character name to find a fandom community or an icon community for the fandom, or the Google trick but with site:livejournal.com. Icons tend to be a bit more artsy with more use of textures and creative cropping.
Other roleplayers: This is a last resort as it's more effort and a little stalkery, and mostly only works for actors in particular roles, not musicians or other celebrity types. Google site:insanejournal.com or site:dreamwidth.org with "application" "canon name" "character name", or try "taken characters" instead of "application". The goal is to find other people's character journals and hope that they've credited their icons so you can go to the icon makers.
I hope this is useful to someone! Feel free to add anything you use as well.