Here is my take on KGBFOAM filtering:
The Fuel Rats have an entire spiel (and web page) about KGBFOAM filtering, but in my opinion it perhaps misleads people a bit into thinking that they must always use it, lest they become stranded out there. In my experience, knowing about KGBFOAM star types is very important, but filtering the galaxy map with those types is for the most part unnecessary, even when you are using the galaxy map route plotter. Filtering the galmap with those star types can be useful in some situations, but in general it's not that crucial. It's much more important to know and remember those particular star types, but most often you don't need to outright filter the galmap.
As you pointed out, you indeed miss many cool systems if you filter by KGBFOAM. (After all, those are the "boring" star types, besides brown dwarfs and T Tauri stars.)
Here is how I travel the galaxy, when I'm using the game's own route plotter (using Spansh is an entirely different thing with its own unique tactics):
Just have all star types visible, and plot as normal. Every time you jump to a scoopable star system (which you'll usually see immediately after starting the jump, which is where knowing the "KGBFOAM" star types is useful), just scoop up.
If, however, you are getting several (three or four) consecutive non-scoopables in a row, quickly check the galaxy map: Does the "fuel star" symbol appear on the solid line? If it does, then you are fine, just keep going on.
(Ok, if the first scoopable star on your route is the last system on the solid line, theoretically you could just barely run out of fuel before you can start scooping it, but this is so extraordinarily rare that it's not really worth worrying about IMO. After literally tens of thousands of jumps I have yet to encounter this situation. It's so rare. The distances would need to be just perfect for this to happen.)
But now the important question: What if the "fuel star" symbol is not there (and there is a dashed line after the solid line)? Meaning that none of the stars on the solid line are scoopable? Now here's where you need to perform a special maneuver and make a detour.
More particularly, instead of going on in your route, search for a nearby KGBFOAM system and jump there instead. Don't plot a route there, just select that system and jump there. After you have filled up you can open the galaxy map and it will re-plot to your original destination automatically.
It will help finding a scoopable system (particularly in those vast brown dwarf / T Tauri fields near the bubble) if you have the "star type" filter selected: Look for yellow or blue systems nearby. Those are scoopable. (Also bright red ones are, but they can be hard to distinguish from the slightly less bright red systems, which are brown dwarfs and T Tauri stars. The yellow and blue ones are easiest to spot.) To double-check, check the star type in the system's info box.
If you happen to be in an area where you just can't see any yellow or blue systems, that's when you can actually use the KGBFOAM filter proper, as it will hide all the non-scoopables, making the scoopables obvious. Remember to restore the filter aftwards.