I've been playing this game for a while now, and I still didn't found an effective way to get pixels, any tips?
I just get ridiculously high amounts by exploring and selling the weapons I find in chests. Placing colony deeds in buildings on high tier planets will also yield LOTS of pixels. Huuuge amounts. You don't even need to do any quests for them. Just go to a volcanic planet, dig down a bit and build minimalist rooms with basic furniture and lighting. Separate each room by a door(not platforms) and put up a colony deed. Check in every now and then to collect as much as 800 pixels per deed. Or you might get energy javelins, which are pretty dope. I kill bosses with those. Additionally, asteroid fields of any star system will have absurd amounts of copper, silver, and gold. If you'd like, you can mine the metals there and sell them for quick cash. It won't take long to get over 1000 silver ore.
go find apex villages, they often have legendary hats like cop hats or barrets, sell them for about 1k each