Any species not requiring the winter dormancy would fit this temperature range. Does your windowsill get direct sun, and how much during the winter months? Drosera species need a good deal of sun, or they need bright flourescent lighting. If you can give them enough light, the temperature range you suggest is suitable for all the tropical species from South Africa, South America, all spatulata, pygmy species (if kept within several inches of the lights), the binata complex, D. capillaris, burmanii. Read the above post on natalensis and madagascariensis where I give the names of the South African tropicals. You might get away with D. peltata and D. auriculata. The temperature for the non-temperate species is not the most important concern, except for the South American species, but rather light. A windowsill in winter can be too dark: here in upstate NY it is cloudy almost every day, and supplemental lighting is a must to successfully grow these species.
