Great setup, @julianoliver!
I just started maintaining bikes myself because I didn’t want to pay high prices for a mechanic to do regular tasks.
I was also really frustrated of not being able to start or finish a task because some obscure tool was missing, so I ended up buying a set:
There is also an XL version of that set but it probably has more than you need:
On top of the (small) set, I got a torque wrench, soft mallet, chain checker, quick link pliers, bike stand and grease.
Since I really don’t have a clue, this also helped me a lot: