Mega Man X3/Sub Tanks

Neon Tiger
The Sub Tank is at the plain sight. Use the dragonfly platform to get it.

Blizzard Buffalo
Get Leg Upgrade. Backtrack all the way back to the last ladder you climbed, climb up the wall, jump to the right, perform a vertical air dash, and stick to the left to get the Sub Tank.

Tunnel Rhino
As you proceed the tunnel area, climb up the open ceiling on the right wall to get the Sub Tank.

Volt Catfish
Get at least two Ride Armors. At the last area of the stage, climb up the far right wall, get on the Ride Armor Platform, select it (except Frog), go back down to crash through the floor, proceed to the left, jump off the Ride Armor, and get the Sub Tank.