If you’ve been wanting to talk about your work yn Gymraeg but struggle to find the right words, then the Career Wales site is a great place to start. I’ve been wanting to learn more vocab specifically related to my work and came across it during my search, and it’s a great resource because it’s basically a beginners guide for students explaining what a certain job is and the type of activities undertaken, so it’s really useful for picking up relevant vocab.
Teuluoedd Swyddi. Jobs according to category - technological, creative, service and business.
A i Y. A to Z of jobs.
(I’ve linked to the Welsh pages, but you can switch to English at the top of the page.)