Exactly what it says on the tin. Accessories that match so well they could have been designed as part of the original spite. For instance, look at F!Morgan and the Tactician’s Hat EX. The colour scheme is just chef’s kiss a flawless match.
And then there’s Eliwood, rocking Hríd’s crown so well it looks like it was hand-crafted to nestle in his hair.
And finally, B!Hector, whose helmet probably was made to match the armor but it’s just done so well.