Looking at the Tower of Mystery, I just came up with another idea, except it is one that would probably require a lot of work. But if you have any Dev friends who are into different genres, maybe you could collaborate.
There could be other Towers. A pure platformer tower, like Mario, an action platformer tower, like Castlevania, a Roguelike tower etc. etc. Like the minigames in Final Fantasy.
Each one wouldn't need to be incredibly well thought out, how detailed they would be would be up to you.
Again, this is all very long term. Something to return to once you've dealt with the other 93,000 things on the list.