Experimental items?

[Choupax]

What are those? half yellow half blue?

[Sombrero]

They have specific affixes (12 in total so far) that can't be obtained anywhere else, can't be obtained through shards either. These affixes have fairly unique effects that are either hard to come by usually or straight-up impossible. Some can be kind of build defining too.

[DecalMan]

All trash

[Choupax]

Thanks