This tool will help you find a grind fight. At this time, it is primarily intended for use with Final Fantasy IV: Free Enterprise. If the D.Machin fight is added at some point, that will also be applicable to vanilla.
Grind Fight Selection
Possible Seeds
Documentation
In order to use this tool, simply follow these steps:
Determine which grind you're interested in, and read the description to determine where to save and reset (and other important notes about the grind).
Every time you get an encounter, select the tile on which you got the encounter. Select the exact formation you got by clicking on it. (Technically, you can skip selecting the formation, but it's highly recommended and may be required to differentiate seeds in certain instances.)
When you're done with a given map, simply click Next Image to move to the next map.
If your only available option listed in the Possibilities section is Reset, you should reset and reload your save to try again. The reset points are optimized to minimize the average time spent searching.