My #conlang Kwanyani needs a tone system. I've been "window-shopping" for one for a while, but I've finally settled on a two-level register tone system.
For now I allow all of the melodies L, H, LH, HL, LHL, and HLH. (I think it would be more interesting to disallow some of them, say LH and HLH, to reduce the symmetry a bit.) The last tone align to the last syllable in the word. The first tone spreads backwards to the beginning of the word, if there are more syllables than tones.
In compound words the two melodies are joined and repeated tones are merged, so LH + H → H and HL + LHL → HLHL. The new melody is achored at the last syllable of the compound word.
I got much inspiration from this article (Composite Tone in Mian Noun-Noun Compounds): https://hal.science/hal-03618121/document
Adding the tone to my grammar document feels like one of those Bob Ross moments. You know, when he has a nice painting of a lake in front of a forest in front of a mountain, and then he just paints a huge foreground spruce that covers the left third of the painting...