There are a lot more options for adding winter interest to your pots than the standard pansies and ornamental kale and cabbage.
Pansies are still the best to plant over tulips and narcissus as the bulbs can easily grow up through the roots. There are lots of colors and types including some very nice, small-flowered violas. The breeders come out with new ones every year. Cabbage and kale will look good through late winter, but will begin to "bolt" as the light increases. This makes them tall and leggy, so I usually get 4" pots and plant them tight together removing any yellow leaves as they show up. If there are bulbs under the cabbages, you can cut them down when the bulbs start to emerge. In pots cabbage and kale combined with tulips or narcissus does not work too well.
If I am doing bulbs, I like a nice pot of one thing -tulips, narcissus, grape hyacinths, crocus (a brief show), large daffodils, Dutch hyacinths, or even alliums. The alliums (ornamental onions) are spectacular, but their foliage does not look good by the time the flowers are up.
The growers have come up with fall planting "programs" to add color to pots and containers. There are some very good plants in these; one group is called "fall magic". You can use 4" pots or gallon cans depending on how much room you have. Remember that by the time you buy fall plants, they are finished growing for the season, so buy a few more and plant tight.
Here are some of the best with a few comments.
Cabbage and kale: shorter is better; they do not grow much after planting.
Carex testacea, carex flagelifera, carex "frosty curls": all good plants, but will dominate your pots if left in for over a year.
Ajuga: a nice accent with dark glossy foliage; low.
Ceratostigma plumbaginoides: a ground cover with very late blue flowers and colored fall foliage.
Euphorbia 'Blackbird', 'Helena's Blush', and any other form: there are some nice white and green variegated ones; mid-size.
Bergenia: glossy green, squeaky foliage; large scale.
Lavender: good for winter if lots of light; grey foliage.
Henchera: there are many forms and almost any color. Look for 'Crème Brulee', 'Green Spice', 'Licorice', 'Key Lime Pie', Peach Melba', 'Palace Purple'; mid-size and wide.
Salvia officianalis: Sage - the variegated leaf forms; need good light; mid-size.
Chrysanthemums: in flower for about 3 weeks; buy in tight bud; tall.
Asters: same short flower season as above, but blues are good; short; usually in 4" pots.
Dracena (also called 'spike'): green, spiky foliage; tall; also comes in red.
'Festival Grass': a new red foliage; dracena-like plant; hardy and dominate; will take over a pot, but spectacular color; tall.
So fill your pots nice and full with all these autumn colors for a show that will last into January - weather depending of course.