For years, I had been vaguely dissatisfied with the options available for minifig bases. Because I use a 1-inch grid, I need something three studs wide or less. This rules out the bases that come with collectible minifigs or Dimensions characters. 3x3 plates are very rare, so I usually ended up using 2x3 plates. These were less than ideal, because on a cloth surface they often tip over. There are some off-brand solutions, but I don't like buying expensive custom parts.
Recently, I realized that wheels placed sideways make perfect bases. The rubber gives them a weight and grip that make them more solid and resistant to falling over, and several types of wheel fit nicely in a 1-inch grid:
I have a large bucket of wheels that came with bulk lots, just sitting around waiting to be used somehow. The only constraint is the number of 2x2 plates with the pin in the bottom.
There are even some old wheels that already have studs attached:
The wheels are taller than baseplates, which can look odd, but I suspect that we will get used to it quickly.
And while while the wheels are slightly better for minifig bases, they are much better as the bases for flying creatures:
You can use a much larger selection of wheels here; they can be taller and don't need to fit in a single square if they are the base for a Large creature. Try to use the kind of wheels that are a bit wider than the plastic tire, so that only the rubber is touching the table.