I'm looking for a manga/anime where the MC used to be really skilled at a certain school but for 1 reason or another has to transfer and is already basically one of the most skilled at the school he just transferred to. A good anime that is similar to this is "Chrome Shelled Regios". If its a manga i want the artwork to be of decent quality please. It puts me off when the artwork isn't that good. I would prefer the MC to be a guy but it's not a must so i don't mind if the MC is a girl either.
 It doesn't have to have to be a transfer now i don't mind if the MC stays in the same place the whole manga/anime anymore. This is just so i can open the suggestions to more types of manga/anime that sound pretty interesting so yep
A added bonus to the anime/manga would be if he kinda hides his powers for a little bit of the manga/anime but again, that's just an added bonus if it's in there haha.
The manga/anime that i have read/seen that are similar to what I'm looking for are: Chrome Shelled Regios (Obviously) Beelzebub Hidan no Aria Negima! Persona 4 Hagure Yuusha no Estetica Ao no Exorcist Infinite Stratos Shokugeki-no SOMA Id(kinda, changes worlds)
Can't think of any others at the moment so if any other ones that i have watched or seen that are not apart of this list i will be sure to add it so no one else needs suggests it
In Negima!, the main character is a teacher who just transferred into an all-girls school as a teacher. He's a genius at his skill/magic. Series completed. Anime available.
In Beelzebub, the most recent long story arcs have the main character transferring into another school. He's the most powerful badass in the school. Series still ongoing, but arc completed; they are returning to their original school. Anime available.
In Hidan no Aria, the main character is an S-Rank Armored Detective a.k.a Butei who has transferred into a new school in Tokyo to search a partner who's able to complement her talents. She is a descendent of a famous detective in the series. Series adapted from an ongoing light novel. Anime available.
There are actually quite a lot of others in my reading list that fit most of the bill, except that the main characters are 1st years student in the school from the beginning, not transfer students. Oh well.
Well, personally I'm also a fan of stories like Regios, and I can tell you finding similar ones is quite difficult, the most similar ones would probably be: Anime: (the first five are based in light novels) Densetsu no Yuusha no Densetsu which not exactly portraits the type of "school transfer" that you want, but I found both of the main characters quite similar to Regios' characters. Hagure Yuusha no Estetica is probably a bit more similar with the main character returning to "Earth" after succesfully defeating the demon lord in another world and enrolling a special school for returnee heroes where he ends up being one of the strongest ones. The only thing is that it has a lot of fan-service(in case you don't like that). Mondaiji-tachi ga Isekai kara Kurusou desu yo hasn't even aired but from what I've read it seems a little bit like what you're looking for, two girls and one boy with special gifts are transfered to another world in order to save a community there from the demon lord. At least in the manga version the main guy was really powerful from the beginning. Infinite Stratos in a way, the main character is forced to enroll the school just for being the only man able to pilot the mechas. Ichiban Ushiro no Daimou, in here he doesn't transfer but just enroll in the academy and ends up learning he's the almighty demon lord which makes him get alienated (then again it also has a lot of fan-service). Dog Days again more of a "transfer to another world" one, the main guy (Cinque or Sink however you want to call him) was the 2nd place in an athletics championship which ends up making him a hero on the other world. It's an original anime. Muv-Luv Alternative: Total Eclipse is based on a visual novel, while it doesn't have a school setting, the main guy gets transfered to a testing facility in Alaska from an elite testing facility elsewhere in America even though he's extremely skilled because of an incident. Natsume Yuujinchou isn't probably exactly what you're looking for but you might as well check it out, the guy changes schools since he is being like passed around between his relatives after being left orphan and being the only one in his surroundings able to see youkai. It's based on a manga which I haven't read but I guess it should be as good. Persona 4 is based on a game, here the guy is transfered for family issues and while he isn't almighty from the beginning it's the kind of MC that's always above the rest of the characters.
Manga: Ao no Exorcist, in a way, even if they never show you the first school he attends he ends up being transfered. (The anime isn't as good as the manga after it enters the filler in ep 15 so you might as well only read the manga) Shokugeki-no SOMA is a brand new series, even if it's about cooking the rest of the setting is exactly what you wanted (then again this is also a bit heavy on fan-service) Asu no Yoichi also has an anime which isn't all that bad, but the manga is better. It has a samurai going down the mountain he lived in and transfering to a school in the city where he's the best fighter. Again, it has its good share of fan-service.
The list ended up being bigger than I expected, I didn't actually think I could find this much when I began writing this, even if not all meet all your requests I hope there's one you haven't seen/read that you like.
Wow thanks a lot for all of those suggestions Out of all of those i have read: Persona 4 Hagure Yuusha no Estetica Ao no Exorcist Infinite Stratos Shokugeki-no SOMA(completely addicted to this one) So i'll be sure to check all of those other ones out though. Again thanks for all of those suggestions