At the moment, the popular type of led for led strip are:
Single color led strip: 2835, 2216, 2110, 5050, 3528, 3014, 5630
Dual color led strip: 2835, 3527 2in1, 5050 2in1
RGB led strip: 5050 RGB, 3535 RGB
RGBW led strip: 5050 RGBW 4in1, 5050 RGB+2835 white, 3535 RGB+2835 white
RGB CCT led strip: 5050 rgb cct 5in1, 5050 rgb+5050 2in1
Build-in pixel led strip: ws2812b, ws2815, sk6812
Normal pixel led strip: 5050 RGB
It's also OK to offer customized led chip for your led strip light, like 3030, 2835 2in1, uv led, etc.
For the brand of the led chip, normally:
For flexible led strip, sanan chip or epistar chip are the best quality at the moment; at the moment, there is still no brand 2835 led chip which is strong enough to be used in flexible led strip;
For rigid led strip, you can choose the brand you need: Nichia, Osram, Lumileds, Samsung, seoul semiconductor, etc.