Tamriel, The Elder Scrolls
The continent of Tamriel in which The Elder Scrolls games take place is a focal point of magic, and it pervades the landscape. Basic magic (creating a small light, a spark of fire sufficient to light a candle, etc.) are fairly common even among the uneducated.
However, these facets of Tamriel are not always well-depicted in the games. It’s fairly rare to see peasant farmers actually use the magic they supposedly have. The Elder Scrolls games all simulate the continent of Tamriel to greater or lesser extent, and in a lot of cases, what is seen in game does not really match what the games’ lore says. Sometimes this is because the lore is described through imperfect narrators who can certainly be wrong, and other times it’s because of the limitations of the technology, budget, or even what the developers consider fun.
But if you read the lore itself, and assume the greater amount of it is accurate even if it’s not backed up by the games per se, you can see a rather common-magic setting, and it’s pretty cool. The best resource for Elder Scrolls lore is The Imperial Library. Unfortunately, I do not have a list handy of references to how life works with respect to its common magic.
Eberron, Dungeons & Dragons
Eberron is suffused with magic, and as a Dungeons & Dragons setting, there’s a ton of detail out there specifically designed to be used with a tabletop RPG. In Eberron’s case, the common-ness of magic means it has been studied and applied much as scientific principles have been studied in the real world. Thus you get things like the lightning rail (maglev trains based on electricity magic), airships (bound air and fire elementals provide buoyancy and thrust), identification papers (marked with arcane seal to prevent forgery), and so on.
Eberron is a very much “magitech” world, with more than a little inspiration from steampunk and the like. In my mind, it represents a fairly logically-consistent way to handle common magic, because if these spells are available, they should be put to more uses than just clearing out dungeons. Eberron actually does that, unlike a lot of settings (for example, no one in Tamriel has thought to enchant a sealed box with frost magic to make a freezer, and the games do describe problems with food spoilage and the like).
Tippyverse, Dungeons & Dragons homebrew
Emperor Tippy is a poster at a few D&D forums, and he has created the notorious Tippyverse campaign setting, based primarily on the idea that if the Dungeons & Dragons v3.5 game rules, as written, exist as the fundamental physical laws of reality, and there exists enough time, people, and magic in the setting to actually study and use all of them, the Tippyverse is what you get (this argument is extremely controversial, of course). Regardless of whether or not you buy the Tippyverse as the strict logical consequence of 3.5’s rules, the setting is fairly well described and certainly counts as having both extremely common and extremely powerful magic.
The Tippyverse is a largely post-scarcity economy fueled by self-resetting magical traps of things like create food & water and remove disease, plus infinite wish loops to power everything. It’s certainly a unique environment, but ultimately the magic is so powerful that it becomes difficult to justify actual problems – almost everything can be solved quickly and easily by simply casting the appropriate spells, which are almost certainly available in abundance.
But it can still give you some pretty cool ideas. Eberron, in a lot of ways, can be thought of as a setting similar to the Tippyverse, except without the most abusive rule loopholes (e.g. self-resetting beneficial magic traps) and without the high-level spells (humans in Khorvaire, Eberron’s primary continent, mostly max out around level 10 of the potential 20+, and anything about 5 or so is pretty rare).
