Speed Racer. First anime I ever watched; it's so old, in fact, that it predates the word "anime" itself.
And trippy? Even the bowlderized, kid-friendly version that aired on Saturday mornings had cars driving off cliffs and explosions galore. Plus, the episodes were shown out of order (story arcs weren't yet a thing in 1970s children's shows) so it was often hard to tell what was really going on. But for maximum trippiness, I recommend you watch the live-action 2008 movie.
Likewise with
Battle of the Planets, which was the US kid-friendly version of
Gatchaman. I have the anime on DVD, and was actually a little disappointed that the cutscenes featuring 7-Zark-7 weren't included. (They were added to the US version to extend the show's running time, since many of the battle scenes had to be cut down due to excessive violence).
Big fan as well of
Heavy Metal, which mannefriedrich already mentioned. Saw that movie dozens of times during midnight showings in theaters, and bought it as soon as it came out on DVD.
And if we're going for out-there cartoon shows, no list would be complete without
Aqua Teen Hunger Force,
Venture Bros, and
Invader Zim.
timppu: As a small kid, some strange man on the street gave me a small cartoon booklet. Later in my life I deduced that he was a Jehovah's Witness. The cartoon was about a man who broke the heavenly rules (seven of them? I don't know) and in the end ended up into hell.
It was trippy, dark and scary as hell to a small kid, and made me afraid that I will end up in hell. Nowadays I know I am going to hell so I don't fret anymore. Gluttony, jealousy, anger, lust... yep yep yep, been there done that, many many times. Hopefully I can keep doing those also in hell.
You would absolutely love Chick Tracts, then. It sounds like the American version of what you read, and they are so over-the-top that they're actually funny... especially since they were meant to be completely serious.
https://en.wikipedia.org/wiki/Chick_tract