I love
Deep Chaos in both of its color schemes. There's just something about that slanted edge that's attractive to me. Heck, I loved Bakushin back in the day too, and once made Bakushin Leone SA165 WD just to have a bey that's kind of UFO-shaped, widest in the middle and narrowing as it approached the top and bottom.
Other layers and parts I think look swell in my collection include:
Spriggan Requiem (Random Booster 10: Blue)
It's essentially a mirrored version of the stock red version, with the gold from the axes in its god chip and the blue from the god chip encompassing the layer, and it is just beautiful to behold this almost chilling rendition of the layer.
Orpheus O2
I play the viola, and I appreciate the reference to violins/violas in this bey a lot. It's the one Hasbro exclusive I actually like design-wise, although I think it would look nicer in a woody brown to match the whole theme better.
Drain Fafnir (Hasbro Green Glitter/Black Rubber)
Drain Fafnir doesn't have many color schemes, but Hasbro found a way to fill in that hole with that sweet looking forest green color scheme accented with glitter. Heck, the glitter makes it seem like a tranquil forest dragon, sunlight shimmering off its scaly hide as it casts pinpoints of glittery light across the glade. It's one of the only Hasbeys I've intentionally bought even though I already had every part in it from Hasbro, because this green scheme is just that good.
Valkyrie (Random Booster 9: Shadowy Black/Purple)
This copied the color scheme from the Evil Spirit version of αmaterios, and boy does it look good on Valkyrie! That deep, glittery black shrouds the whole layer, and the purple accents it perfectly. It's a nice throwback to days past based off of another throwback to days past.
Sieg Xcaliber (RLC9: Gold/Blue)
Sieg Xcaliber looks so regal in this brilliant golden yellow, and the blue accents it even further. It's like a limited edition recolor, but in an RLC release.
Yell
A unique design for a forge disk with its star shape and thick central weight, but sadly not as good as I hoped it would be.
And I'll given an honorable mention to
Kreis Satan (Random Booster 7: Bubblegum Pink/Light Blue Rollers), if only because it's an incredibly daring color scheme. Sadly, I just can't take a pink Kreis Satan seriously, because pink is just such an un-Satan color. Props for making me laugh though. Another honorable mention to
αmaterios (Evil Spirit Version: Shadowy Black/Purple), which looks good but doesn't quite look as nice as Valkyrie does with that same color scheme.
Cincinnati-based Organizer, and owner of every single currently released TT Burst bey part in at least one color. Hard to think of anything I don't have from MFB either...