500 Manga Creatures, a book that purported to provide manga clipart, might as well have been named "300 Manga Creatures Plus 200 Potential Lawsuits from Game Freak" thanks to its inclusion of somewhat obvious examples of this trope applied to the Pokémon franchise. Kyogre, Dratini, Dragonair, Zapdos, Shuckle, Metang, Metagross, Shroomish, Swablu, and Bagon are just the most blatantly obvious ones.
Actually acknowledged in the book's description, where it claims that the characters include "Digimor (sic) and Pokémon-style creatures", among others.
This H-series has a few characters that may be pretty familiar to some people, but the most-definitely-not-Kekko Kamen heroine is the most obvious example. Justified since AB is basically a parody of Kekko Kamen.
At least two characters are CEs of Mai Shiranui (the director apparently includes one in every project he works on as a Shout-Out, two more are basically the lead females of Gowcaizer renamed, and one more is Mizuki from Gravion given the same treatment.
Go Go the Magician isFlash villain Weather Wizard, just with a different name. This is probably due to the fact that the artist had been given some Batman comics and been told to adapt them into a Japanese style - evidently one of the issues was Detective Comics #353, where Weather Wizard bedeviled Batman for a change. The reason for the name change is a little fuzzy, though. Maybe Weather Wizard's stylin' outfit gave the impression of him being one hip swinger, Clyde?
Similarly "Professor Gorilla" is fellow Flash villain Gorilla Grodd.
Since the distinction between copyright free monsters and Dungeons & Dragons originals would remain obscure to laymen for several more years, Bastard's manga originally featured a Beholder. After getting complaints from TSR's Japanese division the comic's supervisor Mr. Suzuki profusely apologized. The monster was slightly altered with comical arms and legs and renamed the "Suzuki Dogezaemon" for the collected volume. Dogeza meaning "apologizing on hands and knees," the incident gained some entertaining notoriety.
Konami would reference this in their Castlevania games with their own mock-Beholder, the Dogether.
Dragon's Crown has its own stand-in, the Gazer. It may be yet another phonetic nod to the joke.
Early translations of Lupin III had to change the main character into an Ersatz because the original author had never asked permission to create a character based on Arsène Lupin. He would be called "Rupan" or "Wolf" or, in the French version, "Edgar of Burglary."
In a Continuity Nod to the original Lupin's Captain Ersatz, Lupin III was forced to face off against "Herlock Sholmes III."
Gintama featured a large number of Captain Ersatzes throughout the series, most used for short parody scenes, like the intergalactic emperor Breeza, obviously a parody of Freeza from Dragon Ball Z or the old man from the lake, the spirit of Gintoki's sword, who looked pretty much like a red version of the human form of the sword of Bleach's protagonist, Ichigo.
In Yatterman, other than the main characters all being Expy of their Time Bokan counterparts, many one-shot characters in the show are either this for real-life people (like The Beatles or Bruce Lee) or for fictional characters from certain stories (like Heidi or Les Misérables) .