Tulip bulbs can be shredded and thrown out, in the second year they are a lot less beautiful if you leave them in the ground. If you want to keep the bulbs, you can remove the flower head after flowering. Then all the energy of the plant can go to the bulb and the bulb will grow and make new bulbs. In July you can take the bulbs out of the ground and peel off the small and big ones. Keep them dry during the summer and plant them in the garden in October.
Daffodil bulbs can stay in the garden (not in pots). Keep the leaf on the plant as long as possible after flowering. Do not cut the leaf, but leave the leaf and stems until they become yellow (= die). This is how the bulb feeds and comes back next year. In the Fall give some compost or fertilizer, and the flowers might come back for a period of 3 to 6 years during the Spring.
Dahlias are sun-loving plants that are blackened by the slightest touch of frost. Traditionally, tubers are dug up in the Fall, dried off and then stored in a frost-free place from year to year, however, recent warmer winters have encouraged gardeners to leave tubers in the ground. This works most years, but the recent harsh winter resulted in losses. If you do leave them in the ground, mulch well with dry matter.