Anime has long been a 2D medium. Even as animation tools have largely gone digital, with 3D assets used as early as 1995's Ghost in the Shell, anime's general style has stuck to the familiar 2D look, especially on characters. Over time, though, various anime studios have tried to utilize the digital tools at their disposal to create anime with more 3D involvement, from 3D character models for dance and action sequences to the trend of mecha shows (anime that features a lot of mechanical innovation) abandoning 2D for their robots entirely. It's come with mixed results - the attempt to make 3D look and move convincingly like their 2D equivalents is often misguided at best, creating an uncanny valley of sorts between the mismatched framerates and wonky designs.
Still, there are absolutely 3D anime productions out there that are worth checking out. Try D4DJ First Mix, for example. D4DJ is a multimedia franchise about girls forming a variety of DJ groups with everything from a mobile rhythm game to real-life concerts, and First Mix is the anime portion of the series. First Mix follows the main group, Happy Around, as they come together and attempt to make a name for themselves in the music and clubbing scene. The mobile game uses a technique called Live2D to display characters during visual novel-like story sequences, which allows 2D models of characters to move around in pre-programmed ways while maintaining the classic anime look. Live2D is also used in systems like FaceRig and by many virtual YouTubers to animate their avatars in real time.
The D4DJ First Mix anime attempts to capture the feeling of the game's Live2D models with its CG characters, and does so to great success. A common reason anime that try to capture anime style in 3D fail is because of a lack of freedom of expression that hand-drawn, frame-by-frame animation allows. But First Mix's animation studio Sanzigen has been specializing in 3DCG animation since their founding in 2003, and that experience has paid off in the long term. First Mix's characters are expressive, moving around with more freedom than the limited animation anime is known for can usually sustain, giving the show's excellent physical comedy more room to shine than if it was a 2D production. Also, where many similar anime would have a separate set of models to use for things like dance sequences, First Mix can use the same characters for the entire show, making it feel cohesive throughout. If idol shows aren't your bag, Sanzigen used these same techniques to great effect in their recent tokusatsu-inspired action anime D_Cide Traumerei the Animation.
Another studio focused on 3DCG animation, the appropriately titled Polygon Pictures has made a name for itself in the past decade for their instantly recognizable CG style. You can find many of their shows on Netflix, from the supernatural thriller Ajin to their animated Godzilla trilogy. The best example of their work comes in their adaptation of Tsutomu Nihei's sci-fi horror manga Knights of Sidonia. Knights of Sidonia takes place thousands of years from now, when people have long been forced off Earth into space colonies after dangerous aliens called Gauna attacked. Like most Nihei stories, it comes with some deep worldbuilding and amazing action.
Polygon Pictures makes the Knights of Sidonia anime a unique experience with their skill in CG animation by rendering out the frightening Gauna and the mecha ship Gardes that the human characters use to fight them. This allows for all sorts of exciting battles to play out, making for some incredible extended choreography that wouldn't normally be feasible for a TV anime. The freedom of camera range is also used to great effect, highlighting the horror of the otherworldly Gauna during particularly intense scenes. Polygon is actually able to use a plot point in Knights of Sidonia to their benefit - as most of the population in the story's space colony are essentially clones produced through asexual reproduction, Polygon is able to freely reuse just a few character models over and over again without it being distracting, as everyone should look the same anyway. If you want a shorter example of Polygon Pictures animation Tsutomu Nihei's manga on Netflix, you can also check out their short film Blame!.
Finally, perhaps the best example of a 3DCG studio using the medium to their advantage with the goal of creating the feeling of 2D is Orange. Like the other studios listed here, Orange also got into the business in the early 2000s, with their first co-production being in 2013 with studio Doga Kobo on the original mecha anime Majestic Prince. Majestic Prince is one of the earliest examples of CG being used to great effect in the mecha genre to facilitate dynamic action, but they wouldn't fully hit their stride until their first full production in 2017's Land of the Lustrous. An anime about humanoid gems defending themselves from aliens that desire their beauty, Land of the Lustrous' characters are largely shiny and round rock people, instantly making their CG models not only less distracting but even appropriate. That's not the only benefit of Orange's skills, though - they also pioneer in the technique of letting the environment around their CG characters refresh while the models themselves stay static, creating a more natural 2D cartoon feel while still taking advantage of the freedom CG allows. This technique has even been imitated in productions like Spider-Man: Into the Spider-Verse to great effect.
For more of their amazing work, check out their anthropomorphic drama-mystery Beastars, where they have been utilizing all of the techniques they've been honing over the years to create a compelling world that feels so real it is easy to get sucked into. Orange utilizes motion capture to give animators more freedom of expression throughout an entire production, from action scenes to facial expressions. In Beastars, which switches modes freely between a subdued character drama set in a high school and a high-tension crime mystery, this is essential to maintaining the naturalistic movements of the characters that makes it all feel like it comes from the same world, as well as capturing the more intimate emotions of the complex characters.