Which mod is this??

[Suicide Junkie]

Was it perhaps a custom map, rather than a mod?
I made an FTL-map, where all systems linked to a set of "hyperspace" systems, generating warppoints all over the place.

[PvK]

It may not be what you're thinking about, but Proportions has quadrant types with large numbers of warp points, although I changed the default system type to a different type. Any of the quadrant types in Proportions labelled as "Rich" do that (Rich Spiral Arm was the old default).

PvK

[Fyron]

FQM has WP Heavy systems with 2x as many WPs per system. But, you can't really get random maps to have too many criss-crossing WPs (esp. ones that go clear across the map).