I'm the same way. It makes my memory recall interesting. I remember the colors first and then translate them to numbers or letters. Made a college job as a receptionist interesting.
I also 100% agree on names must look appealing by color. We have different colors, but the similarities are stark.
I don't have a complete favorite, but generally anything with R or M are appealing. Room is one I like - dark green, white and blue-purple.
I have a real mix of colors. Lots of primaries and whites/blacks too, but definitely more blues. For example, A is red, K is bright pink, but then V is fuschia and X is brown. I find it interesting that numbers have their own colors, but the letters than make up the name of the numbers don't match. So 7 is a very pale but intense orange, while s-e-v-e-n are yellow, bright blue, fuschia, and tan.
I'm curious how your color preferences apply to your synesthesia. I personally dislike certain shades of orange and yellow, so J and S get unfairly judged.