Oh man do I have you covered… fancy metal responsives is my thing.
By far (in my opinion of course) the two best are
- One Drop Deep State
- YoYoFactory Confusion
These are the gold standard by which everything else should be judged! I’d put Deep State slightly in front, but it’s a close call.
I’d choose the confusion if you prefer a smaller old school bearing, plus it comes with thinner response pads (and a wide bearing) if you want to play it unresponsive. The Deep State uses a recessed standard C bearing. Heavy lube that bearing and it’ll be very responsive indeed; clean the bearing for max spin time, and it’ll be more unresponsive.
Some others that are also excellent, depending on your shape and style preferences:
- Basecamp Sherpa
- Basecamp Moonshine
- Tom Kuhn SB-2
- CoreCo Alley Cat 650b
- TopYo Creater
- Rain City Skills Gamer
- iYoyo 2
One I am not listing here is the Smashing Pip which plays like a square megabrick to me. Interesting … but not one I’d recommend.
As far as responsive plastic goes, my picks are:
- Japan Tech LinkX (h shape, awesome!)
- YYR Fay / Diffusion (v shape)
- YoYoOfficer X-Point (w shape)
- Recess First Base (o shape)
There’s a lot of responsive plastics out there but to me those play the best. And I like strong different shape choices 
