Here's a copy and paste of a post I made about a month ago when someone else was asking about accessories.
These are the things I bought this summer when I purchased my first Blackstone.
For squeeze bottles: criteria: they dont leak as I take them camping https://www.amazon.com/gp/product/B076PT3BD9/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
For spatulas & Scraper: Wanted ones that dont bend and hold up well without breaking the bank. Also I dont like the cutouts that the older Blackstone ones have on them. The newer ones dont have those however so maybe they are better. https://www.amazon.com/Stainless-Steel-Metal-Spatula-Set/dp/B072QT1LYY/ref=sr_1_1?keywords=anmarko&qid=1575082739&sr=8-1
Cafeteria trays: surprised how much I love/use these, such easy cleanup camping, no excessive waste of paper plates etc. Mine were red, pack of six, and a bit cheaper than what the price is showing now. I use them for everything, chopping veggies, preparing steaks, just toss the dirty one aside, grab a clean one, put the cooked stuff on them, let the steaks rest on them etc. Much sturdier than paper plates. But I also find myself using them at home a lot now when going outside and back inside. Easy carrying food. https://www.amazon.com/Carlisle-CT1014-8103-Standard-Cafeteria-Black/dp/B01C5HC1S4/ref=sr_1_37?crid=KRE80XQPYXZZ&keywords=carlisle+food+tray&qid=1575082836&sprefix=carlisle+%2Caps%2C159&sr=8-37
Meat temp pen: its cheap and it works, not the best you can buy https://www.amazon.com/ThermoPro-Digital-Instant-Thermometer-Kitchen/dp/B01IHHLB3W/ref=sr_1_7?keywords=thermopro&qid=1575083104&sr=8-7
Digital Read Temperature for the griddle. Cant find the one I bought
I already owned excellent quality dome lids. Get one! They work great for steaming vegetables, melting cheese, etc.
If you bought the new pro series with a lid, you can make things like pizza really well :) I made it all summer on my smaller 22" with lid and figured out the best base to set the pizza on was a wire cooking rack. I found the pizza stone worked as well but it got very hot directly on the griddle, and I figured it was just as easy to place it on a rack. Either the pizza directly or the stone on rack. So a cheap cooking rack is handy.
Lots and lots of paper towels :)
Get an instant one. I have this one ThermPro TP03
Ok I have a pan, thermometer [ https://www.amazon.com/dp/B01IHHLB3W/ref=cm_sw_r_cp_api_glt_fabc_dl_ZT7P0JSCRVSFGBN63FB0] and salt and pepper ( the grinders)….Do I need anything else? Let me know so I can buy it now
I've used this $13 meat thermometer for years and never had an issue. Haven't even replaced the battery yet.