I'm of the opinion that anime's biggest sin is needless filler and padding, so you find a lot more quality for your time with movies and limited series than long-runners. Really no show can reasonably have 100+ episodes of good ideas, its just not going to happen, anime or not.
Most of these are not super mainstream as anime that requires you to have more than a room temperature IQ to enjoy don't tend to be popular.
Here's some that are available on Youtube:
Movies:
Angel's Egg: a deeply atmospheric, thought provoking short movie. It has only a few lines of dialogue, leaving much of what's happening open to interpretation. Definitely one to play if you are in the mood or something more intelligent. Apparently the creator was going through a crisis of faith, as a Christian struggling with doubt in his faith, when creating this.
Green Legend Ran: A little known anime movie that I saw at a young age and it stuck with me, I've never seen anything quite like it. It has this bizarre presence. A fascinating anime for sure, one that leaves you pondering some of its mysteries. Its got a lot of action and some good music too, so a lot more fast paced than most of these other ones.
Darkside Blues: I'm not really recommending this, but as you can probably tell, I love weird thought-provoking animation. So if you are a masochist for that and want something completely bizarre then check this out. I have no idea what is happening in this, but nobody ever remembers this movie exists besides me, so here you go.
One-shot
Goku Midnight Eye: I wish this series had been picked up, because this one-hour pilot is amazing from start to finish. A gritty, late-80s 'wicked city' style cyberpunk anime full of excessive violence and sexuality (shhh don't tell Youtube but there's nudity here).
Short Series:
One Outs: Written by the legendary author of Liar Game, this story is surprisingly about baseball (a subject I have almost zero interest or knowledge in) and manages to be one of the most compelling stories I've ever seen. Most of the episodes are brilliant with what they do with their setting and characters, there's no predicting this story.
If anyone's ever rented anime tapes/DVDs back in the late 90s/early 2000s you've probably seen this awesome promo music video by 'MANGA' showing off their anime properties, set to a badass KMFDM song:
Many of those are great anime recommendations too. But did you notice that one weird thing that wasn't an anime, '
The Secret Adventures of Tom Thumb'? Whelp, here it is if you're curious. Its definitely strange but not necessarily bad.
