The newest generation of white LEDs are really the way to go! They have the best effeciency/dollars per watt, and you will really save tons of money with them (unless you need the light to actually heat your space). I run lights from HLG which are a great option. The individual fixture(s) you choose would depend on the actual grow/tent size even beyond the amount of autos. I am guessing you are doing at least a 4x4, maybe a 6x6 space for 15 plants? If so this is a great light: https://horticulturelightinggroup.com/products/hlg-550-v2-rspec
You are aiming for a ppfd of around 700 for optimal lighting/photosynthesis. Here is a really helpful link that uses a lot of grow light science if you are interested! https://www.cocoforcannabis.com/how-to-evaluate-and-compare-grow-lights-for-cannabis/
For a budget option the new Mars hydro lamps with white LEDs also give some really nice results, and are more widely available!
Hope that helps! 👍