I know how ridiculous this sounds, but when I lost my favourite pencil in the middle of a big project, I really felt like I couldn't draw. It's the only pencil I've used for at least a couple of years and I couldn't just go buy another as it came from Muji in London, sixty miles away.
So what's the big deal about it? Well, propelling pencils are great for drawing, what with the consistent line width and no sharpening, but this one also has the special quality of feeling like a real wooden pencil, nice and light unlike the clunky plastic types. I've gotten entirely used to it, and love how it feels in my hand every time I pick it up. Fortunately I remembered I'd probably bought an extra one (they're cheap as well) and managed to find it on a shelf, to my great joy (then a few hours later my old one was found on the sofa).
This is a line spacer for making consistent lettering heights when writing text into speech bubbles. A more complex one called the Ames guide, which seems to be the industry standard for hand letterers, offers far more options, but this is plenty for me (and was more available and affordable). I just put a pencil tip into a hole, pull it sideways along the blue triangle guide to give me a baseline for a line of text, and then skip one hole vertically in the same column to make a 6mm space to write within.
Undoubtedly there's a lot more I could be doing with it, but this is enough. For now. It's made a big difference to the consistency of the lettering in my comics. I only wish I'd known about it earlier!
I usually ink with a flexible fountain pen, the red Noodler's Creaper, and finally found a waterproof ink that doesn't a) take so long to dry that you smudge it constantly, or conversely b) start flowing so slowly from the nib that it takes all the spontaneity out of your linework. This is De Atramentis Archive Ink, and I'm very happy with it.
Also, I succumbed to a second fountain pen with a very fine nib, the TWSBI Eco (for 'economy' - about twentynine quid).
Plain old post-it notes have been absolutely ideal for working out page layouts for comics, moving panels, changing panels, adding panels. This is like an analogue form of what digital artists do easily, but before I thought of it I was having to start whole pages over every time I wanted to change something even in an early draft. And that was making me hesitant to even start things. Of course, panels are not all this exact size and shape, so it's a simple matter of taping together or trimming post-its.
My lightbox (or light table? though it's neither a box or a table) continues to be a great time-saver, and allower of experimental layouts which can then be changed without losing everything and starting over. I can place a new sheet of paper over a draft I've sketched and draw it a little better -- hoping to avoid, however, perfecting all the life out of the original, which is liable to happen. Sometimes I'll scan my draft of some element of a scene, print it bigger or smaller as needed, and use the lightbox to easily put it into the frame at a different size.
So, those are mine at the moment. What are your favourite tools?