Similar to Keroro Gunso's humor and premise:
* Gintama: A hilarious, action-comedy set in an alternate Edo period where aliens have invaded Earth. Gintama is known for its absurd humor, wacky characters, and heartwarming moments. It has over 300 episodes and is available dubbed and subbed.
* Fairy Tail: A fantasy adventure anime with a focus on teamwork and camaraderie. While it does have some serious moments, the overall tone is comedic and lighthearted. With over 300 episodes, Fairy Tail is available dubbed and subbed.
* Naruto Shippuden: Though it has darker themes than Keroro Gunso, Naruto Shippuden also has many comedic moments and a strong emphasis on friendship and teamwork. It has over 500 episodes and is available dubbed and subbed.
* One Piece: A long-running pirate adventure with a diverse cast of characters and a wide range of comedic situations. While it has its serious moments, One Piece leans into its wacky humor and over-the-top scenarios. With over 1000 episodes, One Piece is available dubbed and subbed.
* Bobobo-bo Bo-bobo: A surreal and hilarious comedy about a man with a giant afro who fights against an evil emperor with a giant afro. The show is packed with crazy characters, ridiculous situations, and slapstick humor. It has over 140 episodes and is available subbed.
Other long-running anime with a fun and lighthearted vibe:
* Detective Conan: A mystery anime with a clever protagonist who solves crimes using his deductive reasoning. The show is also full of quirky characters and comedic moments. With over 1000 episodes, Detective Conan is available dubbed and subbed.
* Bleach: A shonen action anime with a focus on sword fighting and supernatural battles. Despite its serious themes, Bleach also includes a lot of humor and lighthearted moments. It has over 360 episodes and is available dubbed and subbed.
* Inuyasha: A fantasy adventure anime set in feudal Japan with a strong focus on romance and mythology. Inuyasha also has plenty of comedic moments and a lighthearted tone. It has over 160 episodes and is available dubbed and subbed.
* Fullmetal Alchemist: Brotherhood: A highly-rated anime with a dark premise, but also a lot of humor, heartfelt moments, and a positive message about friendship and redemption. It has 64 episodes and is available dubbed and subbed.
It's worth noting that these are just a few examples, and there are many other long-running anime out there that might suit your taste.
Tip: Check out anime review websites like MyAnimeList or Anime-Planet for a wider range of options and user reviews. You can also use the "Similar Anime" feature on these websites to discover anime that share similar themes or genres with *Keroro Gunso*.