"New algorithms" for tilemap generation?
Maxim Gumin’s WaveFunctionCollapse is fast and produces nice results. A recent paper has been published outlining its technique.
WaveFunctionCollapse is Constraint Solving in the Wild
Combine WFC with a touch of "domain distortion" to add some organic panache:
Or if you have space for several terabytes of high resolution NASA satellite imagery, you can always use that as a training set ;)
A step towards procedural terrain generation with GANs