If you need lower MOQ on stickers I suggest this etsy shop! They do buttons and stuff, too. I usually message her for a custom listing since I get about 100 stickers between 5 designs.
For charms, I use Chilly Pig Creations. They're based in the US and have never done me wrong. You can buy a sample pack from them to see the different finishes and whatnot!
Here are some of mine, they're characters from my comic. These are 1.5", but most of the other ones I do (fanart) are 2". You have to buy the keychain parts and accessories separately.
There are others, like AcornPress or Inkit Labs, but they are either inconsistent with their time table (Acorn) or just... really expensive (Inkit). If you are willing to go to a china manufacturer in order to go cheap, I hear good things about Vograce on Alibaba, but honestly their image quality doesn't look as good from what I've seen.
If you do order merchandise from anyone, though, MAKE SURE your files are setup correctly. Most suppliers have instructions on canvas size and whatever else they need from you. For charms you usually need Photoshop if they want you to prepare a cut line.
If you think you want to get into the merch game and start selling at conventions, the facebook group Artist Alley Network International is an EXCELLENT resource. They're kind of strict on the rules because of how big they are (make sure to read the pinned post in its entirety), but it's been the single most helpful community for me. Before posting in there with questions, make sure you search the group to find posts with topics like yours and take a look at the group files. There are lists of manufacturers and a lot of other useful information in there.