I haven't had any trouble with any plants at cooler temperatures (60-70 F). So far, I've tried hygros (siamensis, green, rosenvarg), xmas moss, glosso, dwarf hairgrass, pennywort, hornwort, bacoba carolinia, ludwigia glandulosa, dwarf sag, anubias nana, anubias nana petite, java fern, and a few others that are escaping my memory.
I selected these plants because they are hardy and have fairly wide temperature ranges (for the most part). I assume most plants that have a temperature range starting in the 70's would do fine down to about 60 degrees. Best way to find out? Just buy some and throw it in a cooler water tank...thats how I did it. Don't completely trust what you read online--not many people keep a cool-water tank, so information is sparse and misleading.