Hey thanks
If you go yellow i whould go with a darker yellow tone in combination with black.
Like black doorpannels / dashboard / sidepannels
yellow doorinserts with black stitches, black shift / e.brake boot with yellow stitches
seats - sideflanks in black and the middle in yellow like my seats but where the red is goes yellow
it realy has to be a dark soft yellow tone so it doen't bite your eyes.
royal blue with black
If you live in colder climat areas you can use Alcantara or a good microfiber material and for hotter climat areas you can use a mesh fabric for better breathing and sweat transportation
Watchout for lightfastness / resitance to fading it must be better then 5
8 it max = good
1 is min= pour
and the material ha to be scuf resitance over 30.000 martindale its better for cars if you take for example only a 10.000 martindale fabric it will wear mutch faster.