Bulbot
Bulbot is the worst Robopon in the game. It has low HP and attack.

Battery combinations
Boomer: Air + Air
Bulbot: Hyper + Hyper
Bulbot: Hyper + NiCD
Bulbot: Mangan + Air
Bulbot: Mild + Mangan
Bulbot: NiCD + NiCD
Bulbot: Normal + air
Bulbot: Normal + Mild
Bulbot: Normal + NiCD
Bulbot: Normal + Normal
Fighter: NiCD + Air
Granite: Mangan + Mangan
Hippon: Hyper + Mangan
Leaky: Mild + NiCD
Meddy: Mangan + NiCD
Sumito: Normal + Mangan
Ta-daa: Hyper + Mild
Timzup: Mild + air
Wobble: Normal + Hyper
Woolly: Hyper + Air

Negapon
Once you unlock Marvel Lab, enter it. Make sure you have room for at least one more Robopon. You should see a building directly in front of you. Go to the left of that building. Once there you should see a dog. Talk to it. It will tell you to input a password. Enter '9'. The dog should give you Negapon. Negapon is very powerful. It turns into NegponX and Gatspon.

Unlimited Mushrooms
When you find a Mushroom of any color, get it and store it in your warehouse. Then, leave the room/area that you are in. When you return, the Mushroom will have respawned. As long as you keep storing them in your warehouse, you can get an unlimited amount of Mushrooms.