Ok so I'll start with the main works.
For starters there's Madoka Magica - This is basically just the TV series told in manga format in 3 volumes. There's some minor variations compared to the TV series, one notable example is how when Sayaka hears the those two guys speaking on the train it is heavily implied she kills them, where in the TV series it's left open with the creators even saying she didn't. Other then that it follows the series closely. Unlike most animes I should note PMMM is in the minority of ones that was anime first and a manga second. The art style is alright if not mostly basic. It definitely doesn't have the same flare and detail as the TV/first 2 movies did but otherwise it's not bad looking.
All 3 volumes are out in English and available in stores
So next we have The Rebellion story - Again, 3 volumes and it follows the 3rd movie closely with a number of various minor variations. Out of all the mangas this is quite honestly the best one. The art style is *amazing* and like the anime the story is just incredible. They really went all out for this. Just to give you an idea of how incredible the art is:
I'm having trouble finding more atm since the site I usually use is down but trust me this is only the tip of the iceberg. The art is seriously gorgeous and draw dropping on some spots.
None of the volumes are current in stores yet. They should start getting official English releases starting in December with the other two volumes pushing into early next year
Next is the spinoffs and such.
The first and most notable one is The Different Story - So out of all the spinoffs this is definitely the one you want to check out the most and is the only one I'd really call a must read for any Madoka Magica fan. It's 3 volumes long and it acts as a prequel story centered mainly around Kyouko and Mami when they first became magical girls and takes place in an alternate one of Homuras timelines before the TV series one. As the TV series suggests the two knew each other before the events of the TV series and this expands on that relationship. It's in the same vein as the original story in that it's quite emotional on a number of parts and really gives you more of an in-depth look at their relationship well they're the magical girl noobies. As the story reaches its later stages you see a different timeline and how things play out there. You'll learn a fair bit more about Kyouko and Mami in this. Imo this is well worth it since they didn't get quite as much screen time in the series so it's great to see them expanded on more. It's also easily considered canon with the rest of the series so worth taking a look at. The art style is pretty much similar to the original Madoka manga. It's good although not at TRS's level of hnnnnnnnnngness.
All 3 volumes are out in English and available in stores
Next is Oriko Magica - This one is 2 volumes (and an extra volume which I'll go into next). This one is based in one of Homuras alternate timelines before the TV series where there's an anomaly in the form of a magical girl named Oriko. Oriko has the ability to see into the future and basically sees what is coming in the form of Wulpurgis and Kriemhild Gretchen. Her and another magical girl set out to stop it. It deals with most of the main cast, first focusing on Kyouko and then bringing in the other main cast that you're familiar with as it continues. It's a rather interesting concept and cool in that you get to see several magical girls unique to this story although personally I feel the story is kind of rushed and the pacing suffers as a result. The art style is also bit off, and some of the characters well being recognizable just look a bit crude compared to their TV series counterparts and compared to the other main mangas. All in all this manga is a take it or leave it. Not a must read but certainly enjoyable enough if you're looking for a PMMM fix.
Oriko Magica [Extra Story] - is an extra 1 volume story that takes the characters from Oriko Magica and does an alternate story with them. This is completely separate from the other 2 volumes and doesn't involve the main PMMM cast at all. It's mostly focused on the relationship between Oriko and another magical girl devoted to her named Kirika. It's an enjoyable one off sort of story for what it is. I liked it a bit more then Oriko Magicas other 2 volumes but it doesn't add a whole lot to the series either way and is still take it or leave it.
Both volumes of Oriko Magica and the 1 volume of Extra Story is out in English and can be bought in stores
Next up we have Kazumi Magica - This one is 5 volumes long. I actually don't have much to say on this one yet. I've only read the first volume so far. The story seems completely separate from the TV series with a different cast. I don't think I've even seen QB in this one yet although he might show up eventually. Yeah I can't say a whole lot yet. It seemed a bit odd when I read the first volume but it might pick up more later... I'll share my thoughts more on this one at some point in the future when I've had time to read it through eventually.
All 5 volumes are translated and out.
Next is Homuras Revenge - This is the newest one out. So far only one volume long. This is one of the few ones that doesn't just go off one of Homuras alternate timelines, instead this one is based in a completely alternate reality from the main story. The story starts out with things playing out like they did at the end of the TV series. Homura has lost against Wulpurgis and Madoka resolves herself to becoming a magical girl. Homura decides to reset the timeline once again before Madoka can make her wish though, only this time both Madoka and QB get pulled alongside her so the time cycle resets and all of them now have a knowledge of how things from the TV series play out. Madoka decides that now that she knows everything her and Homura can work to beat Wulpurgis without her becoming a magical girl and QB continues to be the little **** that he is and screw everything up. This mainly follows the same events as the TV series although there's some minor variations which end up starting to make a larger difference. Due to QB being that lil **** that he is basically everyone besides Madoka ends up hating Homura even more then they did in the original series and she finds herself dealing with a lot more obstacles then she did in the original. I have a couple issues with this manga, for one QB blatantly lies on a number of parts, something which it NEVER technically does in the original canon works. The other issue I have is that many of the motivations at the end of the TV series that draw it to the tipping point are just underplayed. Homura despite knowing she's making things worse for Madoka just decides to reset the timeline again just cause, and Madoka despite resolving to become a magical girl just decides to go with things and not become one just cause. The art style is good, probably the best of the spinoffs and is on par with the original manga. Overall it's interesting and has potential but as is I'd call it another take it or leave it for now.
There is currently only 1 volume out in stores with the next volume due out in October
Last one out is Tart Magica - Only one volume out atm for this one. This is a prequel of sorts that is based on Joan of Arc as a magical girl and I think it goes without saying that it far predates the TV series in terms of events. So aside from the main character Joan of Arc (or Tart) there's quite a few other magical girls in this one both of good and not so good variety. the story is a bit odd for a couple reasons. One it doesn't appear like witches need to hide in labyrinths, and also it reveals that magical girls turn into witches almost right away, a fact that the main characters just sort of shrug off and continue on their merry way. It's sort of building things up for a lot of magical girl versus magical girl plots based in the war but it's still quite early on. The art style is pretty decent in this one, I'd say close to being on par with the original series. Overall this one has a bit of promise but is still too early on to make any firm judgements.
Only one volume out with more coming later this year in November.
Aside from those ones there's Homura Tamura and Suzune Magica neither of which are out yet. I know nothing about Suzune Magica but from what I understand Homura Tamura is more of just a comedic spinoff. The first volume of Homura Tamura will become out later this month well the first volume of Suzune Magica will be released in September.
TL;DR
Madoka Magica - 3 volumes - completed - Decent
The Rebellion Story - 3 volumes - Not out yet - Must buy
The Different Story - 3 volumes - completed - Must buy
Oriko Magica + [Extra Story] - 2 + 1 volumes - completed- Take it or leave it
Kazumi Magica - 5 volumes - completed - N/C yet
Homuras Revenge - 1 volume - ongoing - Has potential but so far is take it or leave it
Tart Magica -1 volume - ongoing - Has potential but so far is a take it or leave it
Homura Tamura - not out yet
Suzune Magica - not out yet