I bought more art supplies on the way home today!
A larger sketch pad for working with water and marker. A sepia (!!!!!) fine liner which I predict I will be seriously in love with. Two more copics, since I left my entire collection of markers at home (these two are "pale fruit pink" and "pale blue grey". For skin and metal respectively.) The five warm, peachy colours above that are brush markers I've never tried before that are apparently water soluble in the same way as my current watercolour crayons, so I'm going to give them a try. If they work out then I'll have five extra much-needed skin tone shades.
And of course, I am now officially the coolest person ever with my Yatterman shitajiki. Okay, it was an impulse buy. I saw it and was like "YES I TOTALLY NEED YATTERMAN TO PROTECT THE PAGE BELOW THE ONE I AM WORKING ON FROM INK BLEEDTHROUGH." XD