Lower Norfair Farming Room
|Ridley's Room||Adjacent rooms||Plowerhouse Room|
On the way out, you should use as much of the two-tile-wide island just right of the Gadora (Eye Door) as you can to gain speed, then Space Jump to the right (the island gives more room to build up run speed than the two-tile-wide sections of the floor below the door). As you approach the last floating pillar with Violas surrounding it, you can press Shot and Jump to fire a shot opening the door, then damage boost off of the Viola. This will give you enough invulnerability to avoid taking damage from the first Holtz in the next room.
Firing a beam shot to open the door could introduce lag, so you can use a missile instead to avoid this.
If you don't have enough Power Bombs, you can farm the first two Violas fairly quickly, and still get the dboost off of the last one.
On the way in, you can farm several of the enemies in this room for drops fairly efficiently. The Zebbos will almost always drop either a Big Energy or a Super, and the Violas will almost always drop a Power Bomb.
On the way out, you can do a similarly efficient farm as well.