Alfred is the tool that I was afraid I couldn't have. I tried a few solutions but they just didn't do it for me. Gnome's default search bar is hard to customize and the various launchers out there either installed huge libraries or weren't hidpi enabled. I ended up writing my own launcher. When I hit Win+Space, a terminal opens and runs a script of mine who relies on the fuzzy finder fzf by junegunn. I use it to open files, search the web, log me into websites automatically with KeePassX, handle the music that's being played, etc.
I actually wrote an article on this but I haven't had the time to create the blog I wanted to put it on. If you're interested, give me your email and I'll send it to you with the code I actually use.