+1 for MB Royal Blue.
Also consider DeAtramentis Königsblau.
Royal Blue isn't all that "brilliant", so you might consider inks trending towards Sapphire-Cobalt, such as Diamine Sapphire.
The paper will make a considerable difference as to the appearance and performance of the ink. If the paper is designated for [colour] inkjet printers, then achieving acceptable performance will narrow your choices significantly.
(My wee Ink Reviews often include samples on the inkjet-compatible letterhead 'Royal' paper, which are intended to indicate how inks fare on rather FP-hostile paper.)
Also, when working with highly absorbent papers, the value (light-dark) of the ink drops to the extent that the chroma (brilliance/snap) is compromised - the colour becomes submerged. As a no-low cost work-around, dilution with [distilled] water may be considered. Using a very light hand with a slightly narrow dry nib can offset line-width gain and bleed- show-through often encountered on highly absorbent papers.