Ask HN: How should I use my employer-provided annual growth fund?

People in my company usually use the growth fund to attend conferences - I didn't and am looking for ways to use them. The expense must be _very_ relevant for my job as a software engineer and my growth in that position (e.g. conferences, technical books, online courses) (non e.g. electronic gadgets, cooking classes, expensive mechanical keyboards, 4K monitors).

I've got ~$1000 left on my growth fund. I'm thinking about purchasing couple of technical books and maybe online courses (on golang/elixir). Do you have any recommendations on useful things I can spend my growth fund on?