I can do this too.
Drop some underrated anime series and explain why. I'll start with 2.
Betterman - A late 90s / early 2000's sunrise joint that's vaguely related to GaoGaiGar. It's sort of tonal whiplash between goofy / robot action / and horror. It pulls off the horror pretty well and has a delightfully creepy vibe throughout, largely due to some on point sound work. It has the "pseudoscience if only for macguffin" kinda thing that GGG does as well, with a bit more mysticism thrown in for the horror angle.
Den noh Coil - Sort of a goonies-esque adventure in AR futurism. Kid's all have these AR glasses, they are well integrated into daily life, but there's something dangerous bubbling under the surface, and a group of kids get together to play cyber detective and suss it out. Also has a slight horror vibe buried under a light hearted surface.
