This one took a bit of wrangling to make it work, because I insisted on having the diagonal read 1-2-3-4-5 whle keeping it litsable. Anyways, I like how it turned out.
Rules: It’s a Nurikabe. It’s also a borderless LITS; or equivalently, the filled area must be tileable with tetrominoes such that no two of the same shape share an edge. Lastly, the numbers outside the grid tell how many tetrominoes are in that row/column.