This is a custom made TF logo made in paint.net.
I initially started off by making the TF logo and then began to facepalm at how unoriginal it looked. I came to the idea of adding my 4 most favorite things i know about TF2 to each tile in the logo.
Up-left is australium. It is really shiny and also unfortunately expensive.
Up-right is Halloween spells. The ones in the custom logo are headless horseshoes footprints and the pumpkin bombs effect on a rocket. I traded a lot in spelled items and since i always play on MvM ghost town they are nearly always active for me. This caused me to consider them as "cheap unusuals" back in 2015 and they meant a lot to me ever since.
Down-left is MvM. I had a hard time trying to think of what to draw on this since the gamemode is just TF2 but with robots. I eventually ended up with drawing metal. I really wanted to add some blue lights to it but i have no idea how to implement it without making it look weird.
Down-right is unusuals. I haven't come in contact with unusuals a lot but unusual crone's dome's are really something to behold.