For the past year I have been compiling Majora's Mask art for a Magic the Gathering Commander deck, where every singleton card is an alteration using Majora's Mask fan art. I have probably combed through 90% of all existing GOOD Majora's Mask fanart (MLP x Majora's Mask content is not art), and there seems to be a massive dead space where the Great Bay Temple is concerned. There is a great piece by Mad--Munchkin of Gyorg, but that is it. Since you are one of the more active artists where Majora's Mask is concerned, I thought that I would give you a few ideas of concepts that are seldom bridged in this community.
- Captain Keeta, a sad scene showing him slumped against the bridge
- The Indigo-Go's rehearsing, from a second-person perspective over Zora Link's shoulder as he enters Zora Hall for the first time
- Literally any depiction of the inside of the Great Bay Temple.
- The Giant Turtle, possibly waking up as Link plays New Wave Bossa? No art exists of this character outside of his Manga appearance.
- The masks themselves, not depictions of the characters they came from. Stone, Giant, Bremen, Couple's, Gibdo, Kamero's, Moon (unobtainable but could be cool), Sun, Troupe Leader's, and surprisingly the Boss Remains masks have very little art attributed to them.
I can go on, but I think that these are a good starting point. There aren't many artists who create more than a few pieces of Majora's Mask art, so most just draw different takes on the same concept. Various shots of Skull Kid, the Moon, and the Deku Butler's son are the most popular concepts from all of my searching. This game is still a treasure-trove of art waiting to be made. It is my belief that you, Lunaros, are the artist to do it.