Sometimes you want your casual to be a little fancy. I would say the suede variety usually falls into this category, but sometimes stylized leather or unexpected colors or color combinations sneak in, too. These are best worn with jeans, khakis, cords or shorts (if you will). Most suit occasions call for something a little fancier, but if you're a recreational suit wearer, these might be just the thing to tone it down.
For those who a shoe is a means to an end and not a way to demonstrate personality, simple is probably better. Plenty of oxfords of all formality levels come in the non-adorned variety, and simple is perfectly acceptable in the shoe game. Plain goes with everything. Sometimes the coolest options speak for themselves.
When you first think of oxfords, you tend to think of the old timey detailing that went into men's shoes of yore. The wingtip embellished oxford hasn't disappeared, but it's no longer the only player in the game. Today's versions come in many varieties, some which you've seen and some that are a little updated. Sometimes a little detail is what you need to elevate an outfit, and it's a type of detail that will never go out of style. Well, at least it hasn't after all this time. And despite what you see below, these do come in more colors other than...brown.
For those not afraid of detail but not wanting a footwear throwback, the cap toe is the way to go. There is some visual interest there, but they are still pretty minimal and extremely modern. These go well with a suit and elevate a more casual pant or pant/blazer combination to super stylish levels, though generally these keep things a little fancier.
These are for the risk takers. They're not always the most formal, but they're bright, daring and full of personality and detail. I'm a fan of people who are willing to step out in these in both casual and dressy situations, but I say wear at your own risk because looking clownish is possible with too much effort to make these work.