I'm just getting into BeamNG modding, but I love that there's a fork of the Blender Jbeam editor for 5.x (especially after the 0.39 update added HDR lighting previews that only work in 5.x).
(unofficial) Version 0.2.71 - added a check to prevent duplicate node names during renaming. - fixed broken cross-part beam visualization when dynamic beam coloring is enabled