I know some providers will cater to wardrobe requests and even role play, but most do not own any cosplay costumes and don’t really know the characters. Is anyone aware of providers that specifically cater to cosplay?

...next to nothing on the subject, but I am intrigued by this whole subculture within the hobby. When you say "cosplay", are you referring specifically to Japanese anime or does the term encompass a much wider range of genres and "characters"?

I've never heard of providers working at FurCon, but I do know, having lived in San Jose for 9 years, that Cosplay hooks are not only possible at these events, but likely.  

Great questions!  I'm certainly not an expert in cosplay either.  It's of those check box kinks that I'm looking to cross off my list.  I just know that a number of ladies make a living off of content that is primarily cosplay based (Sia Siberia, Jessica Nigri, etc...)  Part of why I'm asking the question is I don't know where to even purchase these costumes vs if I wanted a school girl fantasy, I know I can order something off of Amazon if the provider doesn't already have that outfit in their wardrobe.  I figured if the provider is already into this, than they might have a catalog of characters that they have costumes for.  As for the sex monsters lol (that had me rolling) I wasn't thinking of dressing up as anyone other than myself in these scenarios.  So I guess unlike the furry kink that someone listed below, I'm more interested in how they look and less about me playing dress up.  Most of the content that you see on the internet are just the girls dressed up with a male actor or dildo and nothing so elaborate as tentacle monsters.

...the attraction of "cosplay" as one of the reasons I had booked a certain porn star before was because she had a passing resemblance to Margot Robbie and had dressed up as "Harley Quinn" one year for Halloween, posting it on her social media which then caught my eye. I didn't think of asking her to show up dressed as "Harley Quinn" though, but had I been more aware of the "cosplay" subculture in hobbying back then, I would have lol!

Completely off topic, but I met a provider once for an outcall to my hotel room.  She must have literally just applied spray tan before our appointment.  When I have outcalls, I like to shower with them if they are agreeable (cleanliness works both ways right?)  The water was literally turning orange.  I remember thinking "there's some implication that I'm not considering right now...."  Of course I was very distracted by other stimulants.  Long story short, when she left, I turned around to look at my bed (only king bed in the room), the sheets were smeared with orange/brown stains.  This was day 1 of a 5 night stay at this hotel...  The awkwardness of standing around the room while the maid changed those sheets paled in comparison to the look she gave me when I tipped her on the way out.  Needless to say, I declined room service for the rest of my stay lol.  I honestly don't know if green and blue smears would have been better or worse!

and childish

that you can't un-see.  I wonder how long it will haunt my thoughts and trigger the old gag reflex?