We’ve discussed LED bases quite a bit. A search here will bring up a few discussions about it.
China owns the LED market so DHgate and other import places are your cheapest bet.
Xtron is very good
It’s also easy to make you own with LED strips.
https://us.banggood.com/Wholesale-Warehouse-0_512345M-SMD5050-RGB-LED-Strip-Lamp-Bar-TV-Back-Lighting-Kit-USB-Remote-Control-DC5V-wp-Usa-1135234.html?rmmds=category