[ZeroGravitas]

Pretty much everything in Bootstrap is gray-scale , with the exception of things with semantic function: red=error/danger, amber=caution, green=success.

The only exceptions are "primary" buttons (which was blue by default but based on the link color the last time I checked), info which is pale blue, and code samples which are pink.

I'm not in the slightest way artistic, but I feel if those (incredibly easily overriden) usages hold you back from expressing yourself with color then you're probably best not to bother and so it's a net-win either way.