Just bought a lot off ebay and these were two parts that stuck out to me.

Earth Wheel:

For Defense/Stamina Hybrid combo:
MF(L) Earth Cancer/Sagittario II 90 CS

For Stamina/Defense Hybrid combo:
MF(L) Earth Cancer/Sagittario/Cygnus TH170/SR200 MB/TB
MF(L) Earth Cancer/Sagittario/Cygnus B:D

GB145 Track:

For Metal Fight Limited Format(MFL):
Gravity Perseus(ATK Ver.) GB145 CF

For Metal Fight 4D Format(MFB 4D):
Flash Scorpio/Cetus GB145 RF/R2F or Diablo Kerbecs GB145 RF/R2F

Earth is very viable for Metal Fight Limited Format for its amazing stamina & defense prowess due to circular shape, OWD and weight.

GB145 is quite heavy and has a great shape synergy with Flash wheel.