(My apologies in advance for any typos, rambles, and incomplete thoughts; mobile Side7 fights me at every keystroke.)
A Video/Animation category would be great. It can include subcats like Basics (free programs that a user might already own, and how to navigate them, to import videos from your phone, trim them, insert clips, and tweak the sound), Animation Software for complex programs, and Application (I guess? Asset Creation, maybe?) for tuts about how to use other types of software to prepare images for animation or as a channel's watermark logo. An example would be using Clip Studio to add rain/smoke/glitter effects or simple blinking to an otherwise static image, or a guide on Adobe Bridge.
Photography should have its own category, and include subcats for understanding Camera Specs, Skills such as developing film, Pro-Tips (preserving high quality resolution in digital photos), and Post/Editing/Photomanipulation techniques. (If a photomanip section is created, please enforce a strict 'no uncredited resources' rule to preemptively stop users from swiping anything they find on google. I know that it's already in the rules, but a reminder wouldn't hurt anyone.)
Under traditional, some categories I would love to see and contribute to would be Carving, Sculpting, Textiles/Sewing, Metal, Leather, Jewelry, Pyrography, Glass, Wax, and Papercraft. In Trad>Other, there could be guides for Tools & Materials (how to choose which type of saw blade, drill bit, thread, wood, glue, or magnets you need), Safety (guides for choosing the right type of glasses and gloves, potential chemical risks to avoid, a basic intro on how not to overload your electrical lines, and 'please don't tamper with microwaves' PSAs), and Workspace (setting up a bench, which tools to prioritize buying, and storage).
Laser-based Equipment might be deserving of a category. This would be for 3D printing, 3D doodle pens, and laser wood cutters/burners. Other specialty equipment like Cricut and sublimation printers could probably get lumped into this category, as well.
Under Information, a Customization category could be the home for CSS, HTML, and BB code guides.