The old tried and true amc7135 drivers, that’s the drivers that started it all. How To Build a Flashlight With Perfect Modes (picture heavy)
The Nanjg 105C with the attiny13 is probably the most common.
There are several guides here on BLF that can be very useful using the search box up in the top left corner.
The thread I linked above is just where it all started, they are way more up to date info now. You can start here.
Guide: how to flash ATtiny13a based drivers (NANJG, QLITE, etc.) with custom firmware