I know that Poland used to have a night glider rating, and some UK pilots did aerotow night checks.
Lights on the tug aircraft, low level cockpit instrment lights and normal runway lighting.
There is apparently to be an EASA Glider night rating, and I suppose the same training would apply?
When duration records existed, beacon lights were put on ridges and ridge soaring was used; duration records were discontinued after they reached several days, and pilots fell asleep killing themselves in the subsequent crash.
While wave lift certainly exists during night hours I am not aware of any intentional night wave flights (although a number of landings have taken place after sunset, it is easy to be deceived by the sun being well above the horizon at 20,000ft when it's sunset on the ground, and it takes a finite time to descend - too fast and it's easy to get an iced up canopy. Car headlights can make a very good makeshift 'flarepath'.)